Aidan O'Brien hails St Mark's Basilica as multiple Group 1 winner retired to stud

The Siyouni colt won all four starts as a three-year-old, his final victory coming in an epic renewal of the Irish Champion Stakes at Leopardstown

Aidan O'Brien with St Mark's Basilica after victory in the Irish Champion Stakes earlier this month. Picture: Healy Racing

Aidan O'Brien hailed St Mark's Basilica as "possibly the best horse we have ever had" after Coolmore announced the multiple Group 1 winner has been retired to stud.

Last year's European champion two-year-old after rounding off his juvenile campaign with victory in the Dewhurst at Newmarket, the Siyouni colt picked up where he left off by claiming Classic glory in the French 2000 Guineas.