Here's a breakdown:
* The Roman Withdrawal: When the Roman Empire withdrew from Britain in the 5th century CE, the island was left vulnerable to invasion.
* The Germanic Invasions: Germanic tribes, primarily Angles, Saxons, and Jutes, crossed the North Sea and began settling in Britain.
* Displacement of Celtic Britons: These Germanic invaders pushed out or killed many of the native Celtic Britons, leading to a shift in the linguistic landscape of Britain.
* Development of Old English: The Germanic languages spoken by these invaders eventually coalesced into Old English, the ancestor of modern English.
So, while the arrival of Germanic languages in Britain is often attributed to a single "invasion", it was more of a gradual process of migration and displacement that lasted several centuries.