Which regions in the western parts of Britain remained free from Anglo-Saxon rule?

Alright, let's delve into the Anglo-Saxon period to understand why Scotland and Wales remained free from their rule. Following the Roman withdrawal in the 5th century, Britain was vulnerable. Various Germanic tribes, including the Angles, Saxons, and Jutes, began migrating and settling, primarily in the east and south. These groups gradually established kingdoms that would eventually form England. However, the western regions of Britain, particularly Scotland and Wales, were inhabited by Celtic peoples who fiercely resisted Anglo-Saxon expansion. The mountainous terrain of Wales provided a natural defense, making it difficult for the Anglo-Saxons to conquer. Similarly, the Picts and Scots in the north, who would later unite to form Scotland, were formidable opponents. While there were certainly conflicts and border skirmishes, these regions maintained their independence and Celtic cultures, distinct from the Anglo-Saxon influence that shaped England. So, Scotland and Wales remained largely outside Anglo-Saxon control, preserving their unique identities.