Rethinking the fall of Rome’s republic
When Julius Caesar crossed the Rubicon — a river in northern Italy — in 49 B.C., leading what was effectively his own personal army, he triggered a set of changes that resonated through the ancient world for centuries afterward. Caesar soon occupied Rome, defeated Pompey the Great and his other rivals, and set in motion the transformation from a republic to an imperial monarchy. The constitutional principles that had guided Rome’s rise, over centuries, from a small village to an all-conquering metropolis were suddenly swept away.Ever since, historians have debated why the republic failed — and how Caesar was able to raise an army that backed him rather than the senate and magistrates of Rome. “These were effectively mercenary armies, loyal to the individual general rather than the city-state,” says William Broadhead, an associate professor of history at MIT. “How did this situation arise?”Using a variety of sources, from ancient...