He was the son of Sir Rhys ap Thomas, the de facto ruler of most of south-west Wales who aided Henry Tudor in his victory on Bosworth Field in 1485 and Efa ap Henry. In the reign of Richard III his father"s loyalty was questioned to the house of York as support grew for Henry of Richmond (later Henry VII of England).
Rhys assured Richard of his loyalty but refused to hand over young Gruffydd, who was only four or five at the time. Gruffydd and Prince Arthur seem to have been quite close. In 1501 Gruffydd was made a Knight of the Garter, and was with Arthur when he returned to Ludlow with his new young bride Catherine of Aragon in December 1501.
And was there for Arthur"s death in April 1502.
On the death of Prince Arthur in 1502, Gruffydd ap Rhys was a prominent mourner. He accompanied the Prince"s body from Ludlow to its final resting place in Worcester.
The following contemporary record gives an account of Gruffydd as he travelled with the "rich chariot" which carried Prince Arthur"s body: "in mourning habit, rode next before the leading horse on a courser trapped with black, bearing the Prince"s banner." During the funeral service for the Prince in Worcester Cathedral, he once again carried Arthur"s "rich embroidered banner."
Gruffydd was present with Arthur"s younger brother Henry VIII of England when Henry travelled to France for the famous Field of the Cloth of Gold in 1520. Gruffydd ap Rhys himself died prematurely in 1521.
He was considered a threat to Henry"s power and was executed for treason on charges widely believed to be false in 1531.
Gruffydd"s tomb is also in Worcester Cathedral.
When Gruffydd was older he became a member of Prince Arthur"s household.
