The collapse of Roman rule in Britain in the 5th century left a power vacuum that was quickly filled by a patchwork of warring kingdoms. As the Roman military withdrew, the island became a battleground for various groups, including the Picts, the Irish, and Germanic tribes like the Angles, Saxons, Jutes, and Frisians. These incoming warrior cultures gradually replaced the Romano-British and Briton populations in the east, eventually coalescing into seven distinct kingdoms. The subsequent centuries were marked by a violent struggle for supremacy, as these kingdoms fought amongst themselves and against external threats, ultimately shaping the England we know today.