In 1915 he was sent to Thomastown Stud in County Kilkenny, Ireland, and later moved to his owner's Ballylinch Stud just east of Thomastown. The Tetrarch had difficulty as a stallion due to a lack of interest, and would be plagued by infertility problems for a number of years. Although he sired only 130 foals throughout his stud career his progeny inherited his blazing speed, and in 1919 he was the leading sire in Great Britain & Ireland as a result of the performances of Tetratema and the filly Snow Maiden. Another daughter (Mumtaz Mahal) won a number of important sprint races and, according to "Thoroughbred Heritage" went on to become one of the most important broodmares of the 20th century.