Marcus Calpurnius Bibulus was a politician of the Roman Republic. He was a conservative and upholder of the established social order who served in several magisterial positions alongside Julius Caesar and conceived a lifelong enmity towards him. In 59 BC, he was consul alongside Julius Caesar. Their partnership was contentious to the extent that Caesar's supporters assaulted Bibulus in Rome's main forum on the eve of an important vote. Bibulus withdrew from public politics for the rest of his term.