Sack of Rome

In May 1084, Italo-Normans sacked Rome, the result of the Pope Gregory VII's call for aid from the duke of Apulia, Robert Guiscard. The pope had been besieged in the Castel Sant'Angelo by Henry IV, Holy Roman Emperor, in June 1083 and called for aid from Guiscard, who was then fighting the Byzantine Emperor Alexios I Komnenos in the Balkans.