sentences:  Henry never successfully invaded Wales and he was obliged to seek compromise with Rhys ap Gruffydd for control of the south.By the mid-11th century, Wales had been united by the Prince of Gwynedd, Gruffudd ap Llywelyn.Gruffudd pushed into Saxon England, burning the city of Hereford, overwhelming border patrols, and proving the English entirely inadequate to respond to Welsh invasions.