Foaled at Straffan Station Stud, near Ardclough, in County Kildare in Ireland, he was sired by Roi Herode (France) out of Vahren.

Dismissed as having no racing potential by some buyers, he was ultimately sold by his breeder to Major Dermot McCalmont and placed under the care of trainer Atty Persse.

In his one real test he came from behind to capture the National Breeders' Produce Stakes by a neck, but that one close finish only resulted after a mix-up at the start that left him four or five lengths back.

There is (as with many star two-year-olds) the question of what The Tetrarch's – and his competition's – continued physical development would have meant to his racing performance at age three.

[2] It is also noted that the 1913 crop of two-year-olds was less than spectacular, and the 1914 Champion Stakes, Ascot Gold Cup and the three British Classic Races for colts were all won by different horses with less-than-distinguished career records.

Lauded for his greatness on the track by racing fans of the day, many appraisals of The Tetrarch decades after his death have been equally glowing.

The United Kingdom's National Horseracing Museum called The Tetrarch a "phenomenon" and report that he was voted Britain's two-year-old of his century.

[2] Mumatz Mahal became an important ancestress in the pedigrees of some of history's most influential sire lines, including Nasrullah, Royal Charger, Tudor Minstrel and Mahmoud.

As for questions regarding The Tetrarch's potential to win at a distance, three sons won the St. Leger Stakes (the longest classic) – Caligula (1920), Polemarch (1921) and Salmon-Trout (1924).