Poule d'Essai des Pouliches
Darius was retired to stud and proved to be a successful breeding stallion. The best of his progeny included Pia (Epsom Oaks), Pola Bella (Poule d'Essai des Pouliches, Prix du Moulin), Derring-Do, Dart Board (Dewhurst Stakes) and Varano (Derby Italiano). Darius was diagnosed with stomach cancer and was euthanised on 13 August 1968 at the Highclere Stud in Berkshire.