Auxiliaries, who were often newly conquered war-like peoples, served alongside Roman legions for 25 years and earned Roman citizenship upon discharge, leading to their children becoming Roman legionaries.

Rome's success can be attributed to its ability to integrate conquered peoples and ideas, often granting them a degree of Roman citizenship.

During the late Republic, the Roman army primarily consisted of indigenous Italians, with the expansion of auxiliaries occurring later in the empire.

The Roman military was a massive force of half a million people, integrating foreigners and turning them into Romans over time.

Rome always wins because, even if they lose battles, they can raise new armies from their Italian allies and half citizens.

The Roman Empire's strength lay in its openness to incorporating foreigners, making them want to be part of the empire and work for it.

The most common source of slaves in the Roman world was war, with soldiers capturing enemies and selling them to slave traders following the army.

The Roman Empire's succession problem was a significant failure of Augustus, who relied on heredity for leadership, leading to a series of incompetent rulers until a shift towards selecting qualified successors emerged.

Roman religion was polytheistic, borrowing many gods from Greek mythology, with different cities having their own patron deities. The Romans had an open-minded approach to religion, often integrating new beliefs from conquered societies into their own practices, seeing them as analogous to their existing gods.