The Tripartite Indenture was an agreement made in February 1405 between Owain Glyndŵr, Edmund Mortimer, and Henry Percy, 1st Earl of Northumberland, agreeing to divide England and Wales up between them at the expense of Henry IV. Glyndŵr was to be given Wales, and a substantial part of the west of England, including the English portions of the Welsh Marches. Northumberland was to have received the north, as well as Northamptonshire, Norfolk, Warwickshire, and Leicestershire. The Mortimers were to have received the rest of southern England.
- Trevor Royle, The Wars of the Roses; England's First Civil War, Abacus, 2009, ISBN 978-0-349-11790-4 pg 95