Treaty of Montgomery

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The Treaty of Montgomery was an Anglo-Welsh treaty signed on 29 September 1267 in Montgomeryshire by which Llywelyn ap Gruffudd was acknowledged as Prince of Wales by King Henry III of England (r. 1216–1272). It was the only time an English ruler recognised the right of a ruler of Gwynedd over Wales. Llywelyn's grandfather Llywelyn the Great had previously laid claim to be the effective prince of Wales by using the title "Prince of Aberffraw, Lord of Snowdon" in the 1230s, after subduing all the other Welsh dynasties. Likewise Llywelyn's uncle, Dafydd ap Llywelyn, claimed the title of Prince of Wales during his reign from 1240 to 1246. However, Llywelyn's supremacy in the late 1260s forced recognition of his authority in Wales by an English Crown weakened by internal division.