Thomas was born in Roscrea, County Tipperary, the son of a poor Irish Catholic tenant farmer who died when George was a child.

Originally forced to press-gang at Youghal, County Cork, where he worked as a labourer on the docks, Thomas deserted from the British Navy at the age of 25 in Madras in 1782.

[3][4] Though he was the favourite general of Begum Samru, due to jealous intrigues of his French rival Le Vassoult (committed suicide in 1795) he was supplanted in 1792 in her favour.

[8] The peace only lasted until 1799, when the Phulkian Misl launched further expeditions against neighbouring Jind and Kaithal and decimated portions of Thomas's large army.

[3] Historian Jadunath Sarkar (1870–1958) describes his conquests as "Oval in shape, with ill-defined and ever-shifting frontiers, it extended 13 to 28 miles in different directions.

"[10] He raised an army of eight battalions of infantry comprising 6000 men, fifty pieces of cannon, 1000 cavalry, including the Jats who made up two battalions of Infantry and one-fourth of his cavalry (paid pensions to them and encouraged them to settle in Haryana, colonisation of land through pensions to sipahis contributed to Haryana becoming a stable military labour market in the 1790s), 1500 Rohilla Muslims and 2000 soldiers guarding his several forts.

George told his biographer, William Francklin,[1][2] "I established my capital, rebuilt the walls long since decayed, and repaired the fortifications (of the 12th century fort of Prithiviraj Chauhan).

I cast my own artillery, commenced making muskets, matchlocks and powder and in short, made the best preparations for carrying on an offensive and defensive war."

[3] At Hansi, he was finally defeated and captured by Patiala's army under General Sahib Singh and had his guns, throne and crown stripped off him.