Tomas ap Rhodri or Thomas Rothery as his name is sometimes rendered in English accounts, de jure Prince of Gwynedd (c. 1325-1363) was the only known son of Rhodri ap Gruffudd

Rhodri ap Gruffudd

Rhodri ap Gruffudd was the third or fourth son of Gruffydd ap Llywelyn Fawr. He was the younger brother of both Llywelyn the Last of Gwynedd, Prince of Wales) and of Owain Goch ap Gruffydd...

 (the youngest son of Prince Gruffydd ap Llywelyn Fawr

Gruffydd ap Llywelyn Fawr

Gruffydd ap Llywelyn was the first born son of Llywelyn the Great . His mother Tangwystl probably died in childbirth.-Hostage:...

, and younger brother to both Llywelyn the Last

Llywelyn the Last

Llywelyn ap Gruffydd or Llywelyn Ein Llyw Olaf , sometimes rendered as Llywelyn II, was the last prince of an independent Wales before its conquest by Edward I of England....

 and Dafydd ap Gruffydd

Dafydd ap Gruffydd

Dafydd ap Gruffydd was Prince of Wales from 11 December 1282 until his execution on 3 October 1283 by King Edward I of England...

. After the death of both Llywelyn and Dafydd, and of their rival eldest brother Owain Goch

Owain Goch ap Gruffydd

Owain ap Gruffudd, , , was brother to Llywelyn the Last and Dafydd ap Gruffudd and, for a brief period in the late 1240s and early 1250s, ruler of part of the Kingdom of Gwynedd .- Lineage :Owain was the eldest son of Gruffudd ap Llywelyn and the grandson of Llywelyn the Great...

 (they all perished between 1282 and 1283), Rhodri became the most senior member of the Aberffraw Dynasty to retain his liberty because he had sold his rights of succession to his brother Llywelyn in about 1270 before he had had any children of his own.

Tomas ap Rhodri - the only son of Rhodri and his second wife - was born in exile in England sometime around 1300 and is thought to have died in 1363. He became the de jure Prince of Gwynedd after the death of his cousin Owain ap Dafydd

Owain ap Dafydd

Owain ap Dafydd , de jure Prince of Gwynedd , was the younger son of Dafydd ap Gruffydd the last free ruler of Gwynedd and self-proclaimed Prince of Wales...

 at Bristol Castle

Bristol Castle

Bristol Castle was a Norman castle built for the defence of Bristol. Remains can be seen today in Castle Park near the Broadmead Shopping Centre, including the sally port.-History:...

 sometime around 1325. His sister, Katherine, married into the former ruling family of Powys Wenwynwyn

Powys Wenwynwyn

Powys Wenwynwyn or Powys Cyfeiliog was the southern portion of the former princely state of Powys which split following the death of Madog ap Maredudd of Powys in 1160...

, now Earls of Powis. Tomas inherited his fathers lands in Cheshire

Cheshire

Cheshire is a ceremonial county in North West England. Cheshire's county town is the city of Chester, although its largest town is Warrington. Other major towns include Widnes, Congleton, Crewe, Ellesmere Port, Runcorn, Macclesfield, Winsford, Northwich, and Wilmslow...

 and Surrey

Surrey

Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...

 (Tatfield). However he parted from his Cheshire estates in favour of lands at Bidfield in Gloucestershire

Gloucestershire

Gloucestershire is a county in South West England. The county comprises part of the Cotswold Hills, part of the flat fertile valley of the River Severn, and the entire Forest of Dean....

 and Dinas in Mechain Is Coed (Powys

Powys

Powys is a local-government county and preserved county in Wales.-Geography:Powys covers the historic counties of Montgomeryshire and Radnorshire, most of Brecknockshire , and a small part of Denbighshire — an area of 5,179 km², making it the largest county in Wales by land area.It is...

). This is not the only evidence of an enduring interest in re-establishing a base in Wales because appears to have made an unsuccessful claim on the Lordship of Llŷn

Llyn

Llyn is the Welsh word for "lake" or, occasionally, "pond" or "pool". The word and its cognates in other Celtic languages , as well their derivatives—including lyn, lynn and lin—appear in many placenames throughout the current and former Celtic world, as, for example, in Dublin and King's...

on the basis that he was the heir to his uncle, Owain Goch .

He did not make any claim himself, at least in public, to the throne of Gwynedd.

He married one Cecilia and was the father of Owain ap Tomas ap Rhodri ap Gruffudd ap Llywelyn Fawr - more commonly known as Owain Lawgoch

Owain Lawgoch

Owain Lawgoch, , full name Owain ap Thomas ap Rhodri , was a Welsh soldier who served in Spain, France, Alsace and Switzerland. He led a Free Company fighting for the French against the English in the Hundred Years' War...

 - who in 1369 proclaimed himself Prince of Wales

Prince of Wales

Prince of Wales is a title traditionally granted to the heir apparent to the reigning monarch of the United Kingdom of Great Britain and Northern Ireland and the 15 other independent Commonwealth realms...

and attempted to regain the throne of Gwynedd and of the Principality of Wales itself. Owain was assassinated in 1378.