Flavius Claudius Julianus, more commonly known as Julian the Apostate, was a Roman Emperor who ruled from 361-363 AD. Some synonyms for his name include "Julian II" and "Julian the Philosopher." Julian is known for his rejection of Christianity and his attempt to revive traditional Roman Paganism. He also played a significant role in Roman military campaigns against the Sassanid Empire. Despite his short reign, Julian's actions had a lasting impact on the Roman Empire and have been the subject of much historical analysis and debate.