Seal: Ido seal
Created by: A group of reformist Esperanto speakers  1907 
Setting and usage: International auxiliary language
Total speakers: est. 2000–5000 (all as a second language; very broad estimate)
Category (purpose): constructed language
 International auxiliary language
Category (sources): based on Esperanto 
Regulated by: Uniono por la Linguo Internaciona Ido
Language codes
ISO 639-1: io
ISO 639-2: ido
ISO/FDIS 639-3: ido 
This article is about the Ido language. For other articles with similar names, see IDO.

Ido (pronounced /idɔ/) is a constructed language that was created to become a universal second language for speakers of different linguistic backgrounds, to be easier to learn than any ethnic language. This intended usage parallels the current use of English as a lingua franca, and of French, Latin, and Greek in earlier eras. Unlike English, which is a natural and frequently irregular language, Ido is specifically designed for grammatical, orthographic, and lexicographical regularity, and to favor no one who might otherwise be advantaged due to native fluency. In this sense, Ido is classified as an International Auxiliary Language. Of the most widely used IALs, the first one is certainly Esperanto, Ido's predecessor; it is disputable whether the second place in usage goes to Ido or Interlingua.

Ido was developed in the early 1900s, and retains a sizeable following today, primarily in Europe. It is largely based on Esperanto, created by L. L. Zamenhof. Ido first appeared in 1907 as a result of a desire to reform perceived flaws in Esperanto that its supporters believed to be a hindrance in its propagation as an easy-to-learn second language. Many other reform projects appeared after Ido: examples such as Occidental and Novial appeared afterwards but have since faded into obscurity. At present, Ido along with Esperanto and Interlingua are the only auxiliary languages with a large body of literature and a relatively large speaker base. The name of the language likely traces its origin to the Ido pronunciation of "I.D." (from "International Delegation", see below) or the word esperantido, "descendant (of Esperanto)". In IDO, it is simply an abbreviation of Idiomo Di Omni (language for all).

Ido uses the twenty-six Latin letters used in the English alphabet with no diacritics. While still being completely morphologically regular, Ido resembles the Romance languages in appearance and is sometimes mistaken for Italian or Spanish at first glance. Ido is largely intelligible to those who have studied Esperanto, though there are certain differences in word formation, grammar and grammatical-function words that make it more than a simple reform project. Ido is a stand-alone language.

After its inception, Ido gained support (estimates generally range around 20%[1]) from some in the Esperanto community at the time, but following the sudden death in 1914 of one of its most influential proponents, Louis Couturat, it declined in popularity. There were two reasons for this: first, the emergence of further schisms arising from competing reform projects; and second, a general lack of awareness of Ido as a candidate for an international language. These obstacles weakened the movement and it was not until the rise of the Internet that it began to regain its former momentum.




Photograph of the International Ido Congress in Dessau, Germany, in 1922.
Photograph of the International Ido Congress in Dessau, Germany, in 1922.

The idea of a universal second language is not a new one, and constructed languages are not a recent phenomenon. The first known constructed language was created in the 12th century by St Hildegard of Bingen under the name Lingua Ignota. It was not until the 19th century, however, that the idea caught on in large numbers with the language Volapük, created in 1879 by a German Catholic priest named Johann Martin Schleyer. Volapük, though popular for some time and apparently with users numbering in the thousands, was later eclipsed by the popularity of Esperanto, which arose from Zamenhof's book Unua Libro in 1887. The simpler grammar and less changed vocabulary of Esperanto appealed to many, and its popularity quickly rose. The first World Congress of Esperanto was held in 1905. However, some within the Esperanto community itself felt that the language should undergo further reform before being officially selected as a universal second language. It was at this time that Couturat formed the Delegation for the Adoption of an International Auxiliary Language.

This delegation made a formal request to the International Association of Academies in Vienna to select an international language; the request was rejected in May 1907. The Delegation thereupon decided to meet as a Committee in Paris in October 1907 to discuss the adoption of a standard international language among the various competitors that had been devised up to that time. According to the minutes of the Committee, it was decided that no language was completely acceptable, but that Esperanto could be accepted "on condition of several modifications to be realized by the permanent Commission in the direction defined by the conclusions of the Report of the Secretaries (Couturat and Leopold Leau) and by the Ido project." This (anonymous) "Ido project" was later suggested to have been primarily devised by Couturat with some help from Esperanto's representative before the Committee, Louis de Beaufront. Beaufront had himself argued for reforming Esperanto before he was selected to the Delegation. His eventual "conversion" to the Ido camp, upon the presentation of that language, was thus consistent with his earlier positions.

Early supporters of Esperanto tended to resist reforms, and the language's inventor, L. L. Zamenhof, deferred to their judgment. Several of the reforms adopted by Ido were themselves proposed at various times by Zamenhof, especially in 1894 when he proposed eliminating the accented letters and the accusative case (referring to it as "superfluous ballast" [2]), changing the plural to an Italianesque -i, and replacing the table of correlatives with more Latinate words (see History of Esperanto and Reformed Esperanto). The custom of keeping the basic rules of Esperanto fixed remains today. Couturat, who was the leading proponent of Ido, was killed in an automobile accident in 1914, which, along with World War I, dealt a serious blow to the Ido movement. Although that movement recovered to some degree in the immediate postwar period, the whole movement of international languages became Balkanized. With the publication of an even more Europeanized planned language, Occidental, in 1922, Ido went into decline. The Ido movement lost a majority of its published periodicals in the subsequent year or so, and the defection of its major intellectual supporter, the Danish linguist Otto Jespersen, in 1928 on the occasion of the publication of his own planned language Novial, seemed at the time to provide a quietus.

Some observers trace the eclipse of Ido to its hybrid character – part Esperanto reform project, part Standard Average European (see Sapir–Whorf hypothesis). In this view, once it was clear that Ido would neither displace Esperanto nor be adopted by the Esperanto community, many viewed its Esperanto-like features as unnecessary baggage and moved on to more naturalistic projects. Those who approved of them tended to return to the larger Esperanto community.

Ido's decline had slowed by the 1930s, and the movement was still a significant force in interlinguistics during the long gestation of the International Auxiliary Language Association's project. Like the Occidentalists, many Idists hoped that IALA would produce a language relatively close to their own preferences. In the end, the radically naturalistic Interlingua was even farther from Ido than Occidental, and (in contrast to Occidental) there was no major migration of Ido supporters to the new language.

Ido's survival during this period was assisted by financial resources accumulated during its heyday (e.g., the chemist Wilhelm Ostwald had donated the proceeds of his 1909 Nobel Prize to an Ido foundation).

The language still has active speakers today, and the Internet has sparked a renewal of interest in the language in recent years. The estimates of the number of speakers range from 2000 to 5000. In comparison, Esperanto has at least 100,000 (Sidney S. Culbert's widely cited estimate of 1.6 million speakers is controversial).

Jespersen, who was present during the ten days of Committee deliberations in Paris and later served as part of the permanent Commission, wrote a history of Ido.[2]

A number of Esperanto supporters have attacked Ido over the years. The Esperantist Don Harlow has characterized Ido's founders as underhanded and conspiratorial;[3] see also Emile Boirac's report in the list of external links; also Gaston Waringhien's “Kulisaj manovroj” (Maneuvers in the Wings) in his 1887 kaj la sekvo, Antwerp: Stafeto, 1980. However, most Ido partisans argue that Harlow's history is polemical and is not consistent with all the eyewitness accounts, such as those reported by Jespersen. Harlow bases his account on material from some other eyewitnesses such as Emile Boirac and Gaston Moch and with other source documentation (such as Zamenhof's correspondence with Couturat and others during the period, as published in the two-volume Leteroj de Zamenhof, Paris: SAT, 1948), to which Jespersen, according to Harlow, would not have had access.


Comparison with Esperanto

Ido flag
Ido flag

In spite of the fact that Ido technically ranks among the three largest constructed languages in the world, its user base is much smaller than that of Esperanto to the extent that the average person has never heard of the language. In contrast to this, many people who have not learned Esperanto still have an idea of its existence, its goals as a language and perhaps even a general idea of how the language itself works. Because of this, often the easiest way to explain Ido is to first show in what way it differs from Esperanto.

Ido inherits many features of the grammar of Esperanto, and in many cases, the vocabulary is similar. Ido shares with Esperanto the goals of grammatical simplicity and consistency, ease of learning, and the use of loanwords from various European languages. The two languages, to a great extent, are mutually intelligible. However, certain changes were introduced to address some of the concerns that had arisen about Esperanto. These include:

Nevertheless, modern Esperanto has received some influence from Ido in areas such as a clarification of the rules for word derivation and suffixes like -oz- ("abundant in") and -end- ("required to").



Ido has the same typical five-vowel system (a, e, i, o, u have their IPA values) as Esperanto, and most of the same consonants, omitting two consonant phonemes used by Esperanto, IPA /x/ and /ʤ/. (The distinctions between /x/ : /h/ and between /ʤ/ : /ʒ/ carry a very low functional load in Esperanto, and so were deemed to be unnecessary in Ido.) Without those two consonant phonemes, the consonants in the language are as follows:

Bilabial Labio-
Alveolar Post-
Palatal Velar Glottal
Plosive p b   t d     k g  
Nasal   m     n        
Tap       ɾ        
Fricative   f v s z ʃ ʒ     h  
Affricate     ʦ   ʧ        
Lateral approximant       l        
Approximant           j    

The accent rule in Ido is regular, but slightly more complex than that of Esperanto: all polysyllables are stressed on the penultimate (second from last) syllable except for verb infinitives, which are stressed on the ultimate syllable—skolo, kafeo and lernas for "school", "coffee" and "learn", but irar, savar and drinkar for "to go", "to know" and "to drink". If an i or u precedes another vowel, the pair is considered part of the same syllable when applying the accent rule—thus radio, familio and manuo for "radio", "family" and "hand".



Each word in the Ido vocabulary is built from a root word. A word consists of a root and a grammatical ending. Other words can be formed from that word by removing the grammatical ending and adding a new one, or by inserting certain affixes between the root and the grammatical ending. As with Esperanto, Ido is grammatically invariable; there are no exceptions in Ido, unlike in natural languages.

Some of the grammatical endings are defined as follows:

Grammatical form Ido Esperanto English
Singular noun -o (libro) -o libro book
Plural noun -i (libri) -oj (libroj) books
Adjective -a (varma) -a (varma) warm
Adverb -e (varme) -e (varme) warmly
Present tense infinitive -ar (irar) -i (iri) to go
Past tense infinitive -ir (irir) N/A to have gone
Future tense infinitive -or (iror) N/A to be going to go
Present -as (iras) -as (iras) go, goes
Past -is (iris) -is (iris) went
Future -os (iros) -os (iros) will go
Imperative -ez (irez) -u (iru) go!
Conditional -us (irus) -us (irus) would go

These are the same as in Esperanto except for -i, -ir/-ar/-or and -ez. Esperanto marks noun plurals by an agglutinative ending -j (so plural nouns end in -oj), uses -i for verb infinitives (Esperanto infinitives are tenseless), and uses -u for the imperative. Verbs in Ido do not conjugate depending on person, number or gender; the -as, -is, and -os endings suffice whether the subject is I, you, he, she, they, or anything else.



Ido word order is generally the same as English (subject verb object), so the sentence Me havas la blua libro is the same as the English "I have the blue book", both in meaning and word order. There are a few differences, however:

Negation occurs in Ido by simply affixing ne to the front of a verb: Me ne havas libro means, "I do not have a book". This as well does not vary, and thus the "I do not", "He does not", "They do not" before a verb are simply Me ne, Il ne, and Li ne. In the same way, past tense and future tense negatives are formed by ne in front of the conjugated verb. "I will not go" and "I did not go" become Me ne iros and Me ne iris respectively.

Yes/no questions are formed by the particle ka in front of the question. "I have a book" (me havas libro) becomes Ka me havas libro? (do I have a book?). Ka can also be placed in front of a noun without a verb to make a simple question, corresponding to the English "is it?" Ka Mark? can mean, "Are you Mark?", "Is it Mark?", "Do you mean Mark?" depending on the context.



The pronouns of Ido were revised to make them more acoustically distinct than those of Esperanto, which all end in i. Especially the singular and plural first-person pronouns mi and ni may be difficult to distinguish in a noisy environment, so Ido has me and ni instead. Ido also distinguishes between intimate (tu) and formal (vu) second-person singular pronouns as well as plural second-person pronouns (vi) not marked for intimacy. Furthermore, Ido has a pan-gender third-person pronoun lu (it can mean "he", "she", or "it", depending on the context) in addition to its masculine (il), feminine (el), and neuter (ol) third-person pronouns.

singular plural indefinite
first second third first second third
familiar formal masculine feminine neuter pan-gender masculine feminine neuter pan-gender
English I thou/you you he she it he/she/it we you       they one
Esperanto mi ci¹ vi¹ li ŝi ĝi ĝi² ni vi       ili oni
Ido me tu vu il(u) el(u) ol(u) lu ni vi ili eli oli li on(u)

¹ ci, while technically the familiar form of the word "you" in Esperanto, is almost never used. Results on Google have shown that while tu is only slightly less common than vu in Ido, ci is used less than half of one percent of the amount vi is in Esperanto. Esperanto's inventor himself did not include the pronoun in the first book on Esperanto and only later reluctantly; later he recommended against using ci on the grounds that different cultures have conflicting traditions regarding the use of the familiar and formal forms of "you", and that a universal language should avoid the problem by simply using the formal form in all situations. Unlike some other languages that use a formal second person pronoun, vi is not capitalized.[4]

² tiu, though not a pronoun, is usually used in this circumstance, because many people have a hard time applying "it" to humans.

It should be noted that ol, like English it and Esperanto ĝi, is not limited to inanimate objects, but can be used "for entities whose sex is indeterminate: babies, children, humans, youths, elders, people, individuals, horses, cows, cats, etc."

Lu is often mistakenly labeled an epicene pronoun, that is, one that refers to both masculine and feminine beings, but in fact, lu is more properly a "pan-gender" pronoun, as it is also used for referring to inanimate objects. From Kompleta Gramatiko Detaloza di la Linguo Internaciona Ido by Beaufront:

Lu (like li) is used for all three genders. That lu does duty for the three genders at will in the singular is not in itself any more astonishing than seeing li serve the three genders at will in the plural ... By a decision (1558) the Idist Academy rejected every restriction concerning the use of lu. One may thus use that pronoun in exactly the same way for a thing and a person of obvious sex as for animals of unknown sex and a person that has a genderless name, like baby, child, human, etc., these being as truly masculine as feminine.

The motives for this decision were given in "Mondo", XI, 68: Lu for the singular is exactly the same as li for the plural. Logic, symmetry and ease demand this. Consequently, just as li may be used for people, animals, and things whenever nothing obliges one to express the gender, so lu may be used for people, animals, and things under the same condition. The proposed distinction would be a bothersome subtlety...



Vocabulary in Ido is based on words intended to give the greatest facility to the most speakers. Early on, the first 5000+ roots were analyzed compared to the vocabulary of English, French, Spanish, German, Russian and Italian, and the following result was found:[5]

In addition, a comparison of Ido vocabulary to the six shows the following for the similarities of Ido to the six languages above:

This is consistent with the fact that Ido is sometimes mistaken for French, Italian or Spanish at first sight.

Comparison of vocabulary with the six languages:

Ido English Italian French German Russian Spanish
bona good ("bonus") buono bon gut ("Bonus") khoroshiy (dobriy) bueno
donar give ("donate") dare ("donare") donner geben darit dar, donar
filtrar filter filtrare filtrer filtern filtrovat filtrar
gardeno garden giardino jardin Garten ogorod jardín
kavalo horse ("cavalry") cavallo cheval Pferd ("Kavallerie") kobyla caballo
maro sea ("marine") mare mer Meer more mar
naciono nation nazione nation Nation natsija nación
studiar study studiare étudier studieren izuchat, shtudirovat estudiar
yuna young ("juvenile") giovane jeune jung yunyi joven

Vocabulary in Ido is often created through a number of official prefixes and suffixes that alter the meaning of the word. This allows a user to take existing words and modify them to create neologisms when necessary, and allows for a wide range of expression without the need to learn new vocabulary each time. Though their number is too large to be included in one article, some examples include:

New vocabulary is generally created through an analysis of the word, its etymology, and reference to the six source languages. If a word can be created through vocabulary already existing in the language then it will usually be adopted without need for a new radical (such as wikipedio for wikipedia, which consists of wiki + enciklopedio for encyclopedia), and if not an entirely new word will be created. The word alternatoro for example was adopted in 1926, likely because five of the six source languages used largely the same orthography for the word, and because it was long enough to avoid being mistaken for other words in the existing vocabulary.[6] Adoption of a word is done through consensus, after which the word will be made official by the union. Care must also be taken to avoid homonyms if possible, and usually a new word undergoes some discussion before being adopted. Foreign words that have a restricted sense and are not likely to be used in everyday life (such as the word intifada to refer to the conflict between Israel and Palestine) are left untouched, and often written in italics.


Ido-speaking community

The vast majority of Ido speakers find out about the language after learning about Esperanto, and so the percentage of Idists (sometimes called Idoists) who know Esperanto is much higher than vice versa. The largest number of Ido speakers is found in Germany, France, and Spain.

As with all constructed languages, gauging the number of speakers of Ido is an extremely difficult task. Moreover, it is also necessary to distinguish between the number of Ido speakers and Ido supporters. Ido resembles Esperanto, and many Esperantists have learned Ido out of curiosity while still not using it, preferring to support the more well-known Esperanto movement instead. On one Esperanto bulletin board was written the following:

Mi provis Idon antaŭ Esperanto, kaj alvenis konklude: la diferoj estas efike trivialaj, komparite al pli gravaj koncernaĵoj (kiujn mi ne detalos ĉi tie). Pro tio mi elektis subteni Esperanton, kaj ne subteni Idon, kvankam eble mi lernos Idon por hobio. Tamen via id-vortoj estas bone komprenebla al mi, kaj mi uzus Idon, se ne ekzistis tre pli subtenita lingvo.

I tried Ido before Esperanto, and came to conclude that the differences are in fact trivial, compared to larger concerns (that I will not go into detail about here). For that [the larger speaker community and volume of material] I chose to support Esperanto and not to support Ido, though I will be able to learn Ido as a hobby. However, your writing in Ido [responding to an Ido speaker] is comprehensible to me, and I would use Ido if there did not exist a much more supported language.

It is possible to find trilingual discussions of this nature on the Internet in English, Esperanto and Ido, each understanding the other with little problem.

A number of Esperantists viewed the schism of Ido as a mixed blessing, and a number of writings show that some were inversely glad to see those who were interested only in creating a perfect language by constantly reforming it leave the fold so that those remaining could work on using and promoting the language itself. However, these "constant reformers" eventually moved on to other reform projects, few of which survived much beyond the deaths of the authors themselves, and Ido has remained constant since then—it is safe to say that were Ido a community of language reformers during its early days, that this is not the case anymore.[7]

A small sample of 24 Idists on the Yahoo! group Idolisto during late 2005 showed that 57% had begun their studies of the language during the past three years, 32% from the mid-1990s to 2002, and 8% had known the language from before.


Language examples


La Princeto (The Little Prince)

Chapter 17 of The Little Prince; the conversation between the Little Prince and the snake upon his arrival on Earth. The title of the Ido-language version is La Princeto.


–Bona nokto ! –dicis la surprizata princeto.
–Bona nokto ! –dicis la serpento.
–Adsur qua planeto me falis ? –questionis la princeto.
–Adsur Tero, sur Afrika. –respondis la serpento.
–Ha !... Kad esas nulu sur Tero ?
–To esas la dezerto, e nulu esas sur la dezerti. Tero esas tre granda –dicis la serpento.
La princeto sideskis sur stono e levis lua okuli a la cielo.
–Me questionas a me –lu dicis- ka la steli intence brilas por ke uladie singlu povez trovar sua stelo. Videz mea planeto, olu esas exakte super ni... ma tre fore !
–Olu esas bela planeto –dicis la serpento-. Por quo vu venis adhike ?
–Esas chagreneto inter floro e me –dicis la princeto.
–Ha ! –dicis la serpento.
E la du permanis silence.
–Ube esas la personi ? –klamis fine la princeto-. Onu esas kelke sola sur la dezerto...
–Inter la personi onu anke esas sola –dicis la serpento.
La princeto regardis la serpento longatempe.
–Vu esas stranja animalo ! –dicis la princeto-. Vu esas tam tenua kam fingro...
–Yes, ma me esas plu potenta kam fingro di rejo –dicis la serpento.
La princeto ridetis.
–Me ne kredas ke vu esas tre potenta, mem vu ne havas pedi... nek vu povas voyajar...
–Me povas transportar vu plu fore kam navo -dicis la serpento.
Ed olu spulis la maleolo di la princeto, same kam ora braceleto.
–Ta quan me tushas retroiras a la tero deube lu venis. Ma vu esas pura e vu venas de stelo...
La princeto nulon respondis.
–Me kompatas vu, qua esas tante sola sur ta harda granita Tero. Me povas helpar vu se vu sentas nostalgio a vua planeto. Me povas...
–Ho ! –dicis la princeto-. Me bone komprenis, ma pro quo vu sempre parolas enigmatoze ?
–Me solvas omna enigmati –dicis la serpento.
E la du permanis silence.
Averto lektenda
La verko La princeto licencesas sub Creative Commons License,
Autoro.- Fernando Tejón,

Mea vido-cirklo (horizonto)

Translation of tune by Russian bard Alexandr Sukhanov from verses by Russian poet Yunna Morits.

Me nule savas la Angla, la Franca, la Greka,
Mea vid-cirklo do restas sat mikra e streta -
En mea vid-cirklo trovesas nur flori, arbori,
Nur tero e maro, aero, fairo, amoro.
Me nule savas la Dana e la Portugala,
Mea vid-cirklo restas sat infantala -
Nur joyi rapide pasant', bruligiva aflikto,
Nur esperi, e timi noktal' es en mea vid-cirklo.
Me savas nek la Sanskrito e nek la Latina,
Mea vid-cirklo es ancien-mod' quale tino
Nur morto e nasko homala, nur grani ed astri
Aden mea vid-cirklo penetras e standas sat mastre.
Mea savo artala esas fakultativa.
Mea vid-cirklo restas presk' primitiva -
En olu es nia afero intima, interna
Por ke kun homaro la Tero flugadez eterne.
Mea vid-cirklon restriktas nur timi, esperi,
En olu trovesas nur amo, nur maro e tero.
Aden mea vid-cirklo penetras e standas sat mastre
Nur morto e nasko homala, nur grani ed astri.

Literature and publications

Extract from The Diary of Anne Frank in Ido from the journal Adavane!, published by the Spanish Ido Society.
Extract from The Diary of Anne Frank in Ido from the journal Adavane!, published by the Spanish Ido Society.

Ido has a number of publications that can be subscribed to or downloaded for free in most cases. The majority of Ido publications are composed mostly of material on various subjects, with a few pages within on the status of the movement and news on upcoming gatherings. Kuriero Internaciona is a magazine produced in France every few months with a range of topics. Adavane! is a magazine produced by the Spanish Ido Society every two months that has a range of topics, as well as a few dozen pages of work translated from other languages. Progreso is the official organ of the Ido movement and has been around since the inception of the movement in 1908. Other sites can be found with various stories, fables or proverbs along with a few books of the Bible translated into Ido on a smaller scale. The site publikaji has a few podcasts in Ido along with various songs and other recorded material.

The online encyclopedia Wikipedia includes an Ido-language edition (known in Ido as Wikipedio); as of December, it has over 14,000 articles.


Recent and upcoming international Ido conventions


References and notes

  1. L. Couturat, L. Leau. Delegation pour l'adoption d'une Langue auxiliare internationale (15-24 October 1907). Coulommiers: Imprimerie Paul Brodard, 1907
  1. Ido-movado. (2005, novembro 15). Vikipedio, La Libera Enciklopedio. Retrieved 19:04, novembro 28, 2005 from
  2. Jespersen, Otto. History of our Language (Ido) from - 1912. Translated from the original Ido available at
  3. Harlow, Don. The Esperanto Book, chapter 3: "How to Build a Language".
  4. Eventoj, no. 103, ISSN 01215-959 X. Ci estas senvalora balasto (Ci is useless ballast). 1996. Available at
  5. L. H. Dyer. "The Problem of an International Auxiliary Language and its Solution in Ido", pp. 101-124 [1], 1923.
  6. Lexiko di nova vorti (lexicon of new words), available at
  7. Chandler, James. Changes in Ido since 1922, from

External links


Overview and answers to common questions


History and opinions on Ido


Pages in Ido and places to learn the language

Ido crest Ido

Grammar | Phonology | Union | Ido vs Esperanto


Beaufront | Couturat | Jespersen | Esperanto and Ido


Esperanto | Esperantido


Wikipedio | Wikivortaro

Retrieved from "http://localhost../../../art/a/h/f.html"

This text comes from Wikipedia the free encyclopedia. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. For a complete list of contributors for a given article, visit the corresponding entry on the English Wikipedia and click on "History" . For more details about the license of an image, visit the corresponding entry on the English Wikipedia and click on the picture.