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The Sheikh Omar Hadid Brigade first emerged from the Al-Qaeda linked (Sinai and Gaza-based) Ansar Bait al-Maqdis group, in a similar way that the Islamic State of Iraq and the Levant (ISIL) emerged from Al-Qaeda in Iraq (AQI). On November 10, 2014, numerous members of Ansar Bait al-Maqdis pledged allegiance to ISIL leader Abu Bakr al-Baghdadi, culminating in the eventual creation of the Sheikh Omar Hadid Brigade on May 31, 2015. In early 2015, Hamas launched a crackdown against ISIL affiliates operating in the Gaza Strip, arresting dozens of individuals. This may have provided an incentive for ex-Ansar Bait al-Maqdis ISIL-affiliated militants to organise themselves, sparking the creation of the brigade in late May of that year.