Ибн аль-Асир
When the crusade entered Constantinople, AlexiosIII fled and was replaced by his nephew. The Greek resistance prompted AlexiosIV to seek continued support from the crusade until he could fulfil his commitments. This ended with his murder in a violent anti-Latin revolt. The crusaders were without ships, supplies or food, leaving them with little option other than to take by force what Alexios had promised. The Sack of Constantinople involved three days of pillaging churches and killing much of the Greek Orthodox Christian populace. While not unusual behaviour for the time, contemporaries such as Innocent III and Ali ibn al-Athir saw it as an atrocity against centuries of classical and Christian civilisation.