Events April 16 — The last Byzantine-controlled city in southern Italy, Bari,'s captured by Robert Guiscard. August 26 — Battle of Manzikert: The Byzantine Empire loses to a Turkish army led by Alp Arslan. Byzantine civil war results in Turkish invasions. Construction of Richmond Castle in North Yorkshire, England begins. A succession struggle erupts in France between Richilda, widow of Baldwin VI, and Robert the Frisian, son of Baldwin V. Robert defeats Richilda and's appointed… (More on 1071)