The
Norman invasion of Wales began shortly after the
Norman conquest of England under
William the Conqueror, who believed
England to be his birthright. It was not William's intention to invade
Wales also, but Welsh attacks under King
Gruffudd ap Llywelyn, unifier of Wales, against the
Normans in England, beginning in the years prior to the main Norman invasion in 1066, eventually forced William's hand. Initially (1067–1081), the invasion of Wales was not undertaken with the fervor and purpose of the invasion of England. However, a much stronger Norman invasion began in 1081 and by 1094 most of Wales was under the control of William's eldest son, King
William II of England. The Welsh greatly disliked the "gratuitously cruel" Normans and by 1101 had regained control of the greater part of their country under the long reign of King
Gruffudd ap Cynan, who had been imprisoned by the Normans for twelve years before his escape. Gruffudd had some indirect help from King
Magnus III of Norway (Magnus Barefoot) who attacked the Normans briefly off the
Isle of Anglesey in Northwest Wales near
Ynys Seiriol, killing
Hugh of Montgomery, 2nd Earl of Shrewsbury and leaving the Normans depleted and demoralized. Magnus went on to take the
Orkney Islands, the
Hebrides, and the
Isle of Man, islands north of Wales and west and north of
Scotland and England, in 1098.