The Roman withdrawal from England in the early 5th century created a political vacuum that led to attacks on the Celts by tribes from the north. Desperate for help, the Celts sought assistance from abroad, which ultimately resulted in the invasion of Britain by the Germanic tribes. This pattern of seeking external help leading to unforeseen consequences can be seen in other historical events as well, such as the invasion of Ireland by the English in the late 12th century following Irish chieftains seeking help from their Anglo-Norman neighbours in Wales.