The Accord of Winchester is the 11th century document that establishes the primacy of the Archbishop of Canterbury over the Archbishop of York.
It originated in a dispute over primacy between Thomas, the archbishop of York, and Lanfranc, the new Norman archbishop of Canterbury, soon after the latter had taken office. The case was first heard by King William at the old Saxon royal capital of Winchester at Easter (8 April) 1072, in the royal chapel in the castle. It was then heard at Windsor at Pentecost (27 May), where the final settlement was made, with William deciding in Lanfranc's favour, and formalized in this document.
This did not end the Canterbury-York dispute over the primacy, as it continued for a number of years after this.
When William and his queen signed the document with crosses, it did not necessarily mean they were unused to writing, infirm or even illiterate. They and all the bishops signed with crosses, as illiterate people would later do, but they did so in accordance with current legal practice, not because they or the bishops could not write their own names.
It (in the CCA-DCc-ChAnt/A/2 version) was also signed by
and additionally, in the CCA-DCc-ChAnt/A/1 version, :
Both versions are endorsed with descriptions and marks in 13th century hands.
The main copies are held at the Canterbury Cathedral archives.(Catalogue entries for the CCA-DCc-ChAnt/A/1 version and the CCA-DCc-ChAnt/A/2 version) There is also one at the British Library