Most historians agree that William died between September 1143 and April or May 1144. They base their view on a memorandum that Guy, Abbot of St. Mary of the Valley of Jehosaphat, compiled in the spring of 1146.
Historians commonly believe that William died between September 1143 and April or May 1144. This belief is supported by a memorandum created by Guy, Abbot of St. Mary of the Valley of Jehosaphat, in spring 1146.