Final answer:
The Anglo-Saxons, including the Angles and the Saxons, succeeded in invading and settling in England after the Romans left around 400 CE, notably not in the 300's as the question suggests.
Step-by-step explanation:
The Anglo-Saxons, a group comprising the Angles and the Saxons, attempted to invade England not in the 300s but actually after the Romans abandoned Britain around 400 CE. They were successful invaders, raiders, and settlers who originated from areas around present-day northern Germany and Denmark. These Germanic peoples fought against the native Britons, including the Cornish and the Welsh, as well as against each other. As Roman culture diminished, the history of England became largely defined by the presence and rule of the Anglo-Saxons until the Norman Conquest in 1066 CE.