Don Juan of Austria
Don Juan of Austria was the illegitimate child of the Holy Roman Emperor Charles V. He rose through the ranks of the Spanish Navy and eventually led a fleet in support of Philip of Spain.
During the Battle of Lepanto, Don Juan had his pet marmoset in tow. When a hand grenade landed in the windowsill in front of Don Juan, the monkey picked it up and threw it back at the Ottoman attackers.
Military Anecdotes, Geoffrey Regan. Carlton Books. 1992