Llywelyn Fawr was born in 1173.  He became ruler of the Welsh Principality called Gwynedd in 1194. 

This is a statue of Llywelyn in Conwy

He became ruler of a large part of Wales and built many castles including rebuilding Deganwy castle in stone.

Deganwy castle ruins

http://www.castlewales.com/deganwy.html

Llywelyn built several palaces including one at Abergwyngregyn, which is about 8 miles from Deganwy.

He married Joan the daughter of king John of England.

The tower part of this picture is believed to be part of his palace in Abergwyngregyn.

http://www.castlewales.com/pen.html

Llywelyn founded Conwy by establishing an abbey of Cistercian monks there.

In his last days he retired to this abbey and died there. 

Llywelyn's seal which was used to seal his letters and important documents.

When King Edward I conquered Wales and built Conwy Castle he made the monks move their abbey to the Conwy Valley and they took the body of Llywelyn with them. 

Llywelyn's coffin which is now in Llanrwst.

http://www.castlewales.com/llyw_cym.html