Sir Delius is out of Whatami (Daylami), who was placed. He is a full sibling to Juan Elcano, a stakes winner who took the Listed Wolferton Stakes and was also placed several times at Group level in England, including at Group 2 level, and a half-sibling to Nkosikazi (Cape Cross), a Group winner in England who won the Gr.3 Hoppings Stakes.

Second dam Wosaita (Generous) was placed once and has nine winners. They include Whazzis (Desert Prince), who won the Premio Sergio Cumani, then a Group 3, and is the dam of the Listed-placed winner Whim, and Whazzat (Daylami), winner of the Listed Chesham Stakes. Whazzat has bred the sire James Garfield, a Group 2 winner and Group 1-placed, the Group 3-placed winner Hallelujah U and the Listed-placed winners Lavender Hill Mob, The Shrew and Morag McCullagh.

Third dam Eljazzi (Artaius) won once and produced ten winners. Besides Wosaita they include Rafha (Kris), winner of the Gr.1 Prix de Diane and dam of the Group 1-winning sire Invincible Spirit and the Group 3 winners Sadian and Acts Of Grace, and Chiang Mai (Sadler's Wells), who won the Blandford Stakes, then a Group 3, was second in the Gr.2 Prix Jean de Chaudenay and is the dam of the Group 1 winner Chinese White.

The family also includes the multiple Group 1-winning sire Mishriff (Make Believe).