Complex sentence: Fratricide among the Scaligeri, when Antonio (1375--87), Cansignorio's natural brother, slew his brother Bartolomeo, aroused the indignation of the people, who deserted him when Gian Galeazzo Visconti of Milan made war on him.
Split into simpler sentences: Fratricide among the Scaligeri continued when Antonio (1375--87), Cansignorio's natural brother, slew his brother Bartolomeo. This aroused the indignation of the people, who deserted him when Gian Galeazzo Visconti of Milan made war on him.