The Amicabilis Concordia, or friendship agreement, is a document renowned these days for the evensongs occasionally held in its name by four colleges dedicated to the Blessed Virgin Mary; that is New College, Oxford, King’s College, Cambridge, Eton College, and Winchester College.  The Concordia was sealed on 1 July 1444 as a quadripartite indenture.

The signed and beribboned menu for dinner after the King’s College versus New College football 1924 [detail]
New College Archives, Oxford, NCA JCR/R/Mallett/4b

New College Library and Archives, Oxford