What caused the Greeks to unify in defense of their culture and way of life

The unification of the ancient Greeks in defense of their culture and way of life was primarily driven by external threats, particularly the invasions by the Persian Empire. Several key factors contributed to this sense of unity:

1. **Persian Wars**: The series of conflicts known as the Greco-Persian Wars (490-479 BCE), including notable battles like Marathon, Thermopylae, and Salamis, galvanized the Greek city-states against a common enemy. The threat of Persian expansion prompted city-states, often in conflict with one another, to ally for their shared survival.

2. **Cultural Identity**: The Greeks shared a common language, religious beliefs, and cultural practices, which fostered a collective identity. The recognition that they were fighting to preserve their way of life, including their democracy (especially in Athens), philosophy, and arts, helped solidify their unity.

3. **Leadership and Alliances**: Prominent leaders, such as Themistocles and Leonidas, inspired and rallied different city-states to cooperate. The formation of alliances like the Delian League, initially led by Athens, played a significant role in coordinating military efforts against Persia.

4. **Immediate Threat**: The reality of imminent invasion and destruction created a sense of urgency. The devastation of areas like Eretria and the advance of Persian forces highlighted the need for unity, as individual city-states recognized their vulnerability.

5. **Mutual Support**: Military cooperation among the city-states, as well as the sharing of resources and intelligence, helped to strengthen their resolve. Joint military strategies, combined efforts in naval battles, and coordinated land defenses were vital in confronting the Persian threat.

6. **Civic Duty and Patriotism**: The idea of defending one's home and way of life instilled a sense of civic duty. This was particularly significant for city-states like Sparta, which had a strong warrior ethos, and for others that relied on a citizen militia.

The combination of these factors allowed the Greeks to set aside their differences, unite in the face of a common foe, and defend their civilization, ultimately leading to Greek victories that preserved their culture and way of life.