Anti-Jewish sentiments usually flared up during times of Muslim political or military weakness or when Muslims felt that some Jews had overstepped the boundaries of humiliation prescribed to them by Islamic law. In Spain, ibn Hazm and Abu Ishaq focused their anti-Jewish writings on the latter allegation. This was also the chief motivating factor behind the massacres of Jews in Granada in 1066, when nearly 3,000 Jews were killed, and in Fez in 1033, when 6,000 Jews were killed. There were further massacres in Fez in 1276 and 1465.