Why so many readers meet Stoicism through Seneca

Seneca was a major Stoic philosopher of the Roman Imperial period who wrote in Latin. The Stanford Encyclopedia says his writings became a central route into Stoicism for later generations: they helped drive a Renaissance revival, and many readers still approach Stoic philosophy through Seneca rather than the fragmentary evidence for earlier Stoics. His influence also appears in the forms he used. He shaped the philosophical letter and the consolation, and the essay On Mercy is described as an early example of writing later called mirror-of-the-prince literature. Seneca is both a source for Stoicism and a lens through which it is often read.