When did the Romans led by Julius Caesar launch their first invasion on Britain?

Caesar carried oujt two expeditions in the southeast of England in 55 BC in 54 BC during his Gallic Wars (58-50 BC). Both expeditions were very brief and on both occasions Caesar returned to Gaul. On the first occasion he was nearly defeated because a storm wrecked much of his fleet and because the sight if the chariots of the Britons undermined discipline among his soldiers. He returned with a larger force and defeated the Trinovantes. However, he was eager to winter in Gaul as there was unrest there. The motivations for these expeditions are unknown.