In 1094, however, there was a general Welsh revolt against Norman rule, and gradually territories were won back. Gruffudd ap Cynan was eventually able to build a strong kingdom in Gwynedd. His son, Owain Gwynedd, allied with Gruffydd ap Rhys of Deheubarth won a crushing victory over the Normans at the Battle of Crug Mawr in 1136 and annexed Ceredigion. Owain followed his father on the throne of Gwynedd the following year and ruled until his death in 1170. He was able to profit from disunity in England, where King Stephen and the Empress Matilda were engaged in a struggle for the throne, to extend the borders of Gwynedd further east than ever before.