Rhys ap Gruffydd, prince of Deheubarth (b. 1132)
Rhys ap Gruffydd or ap Gruffudd (often anglicised to "Griffith"; c. 1132 – 28 April 1197) was the ruler of the kingdom of Deheubarth in south Wales from 1155 to 1197. Today, he is commonly known as The Lord Rhys, in Welsh Yr Arglwydd Rhys, although this title may have not been used in his lifetime. He usually used the title "Proprietary Prince of Deheubarth" or "Prince of South Wales", but two documents have been discovered in which he uses the title "Prince of Wales" or "Prince of the Welsh". Rhys was one of the most successful and powerful Welsh princes, and, after the death of Owain Gwynedd of Gwynedd in 1170, the dominant power in Wales.

Rhys's grandfather, Rhys ap Tewdwr, was king of Deheubarth, and was killed at Brecon in 1093 by Bernard de Neufmarché. Following his death, most of Deheubarth was taken over by the Normans. Rhys's father, Gruffydd ap Rhys, eventually was able to become ruler of a small portion, and more territory was won back by Rhys's older brothers after Gruffydd's death. Rhys became ruler of Deheubarth in 1155. He was forced to submit to King Henry II of England in 1158. Henry invaded Deheubarth in 1163, stripped Rhys of all his lands and took him prisoner. A few weeks later he was released and given back a small part of his holdings. Rhys made an alliance with Owain Gwynedd and, after the failure of another invasion of Wales by Henry in 1165, was able to win back most of his lands.

In 1171 Rhys made peace with King Henry and was confirmed in possession of his recent conquests as well as being named Justiciar of South Wales. He maintained good relations with King Henry until the latter's death in 1189. Following Henry's death Rhys revolted against Richard I and attacked the Norman lordships surrounding his territory, capturing a number of castles. In his later years Rhys had trouble keeping control of his sons, particularly Maelgwn and Gruffydd, who maintained a feud with each other. Rhys launched his last campaign against the Normans in 1196 and captured a number of castles. The following year he died unexpectedly and was buried in St Davids Cathedral.