Why is Philo Judaeus also called Philo of Alexandria?

Philo Judaeus is called Philo of Alexandria because he was born, lived, and died in the city of Alexandria, [Egypt].1

During his lifetime, Alexandria was a major center of the Hellenistic world, and Philo was deeply integrated into its cultural and intellectual life. He was a product of the city's educational system, which emphasized Greek liberal arts and rhetoric, and he spent his career there as a prominent member of the Jewish community. His identification with the city is further underscored by his role as the leader of an Alexandrian Jewish embassy to the emperor Caligula in 39 or 40 CE, which sought to protect the rights of the city's Jewish population following a local pogrom.2