Glacius is out of the placed Predawn (Fastnet Rock), who has three winners from four runners, among them Al Jafara (Pinatubo), a dual winner who was second in the Listed Plenty of Grace S. in the US.

Second dam Perihelion (Galileo) won at three and was second in the Gr.2 Park Hill S. She is the dam of the multiple group-placed Shogun, who won eight races and was placed several times at Group 3 level, and of Qualify, winner of the Gr.1 Investec Oaks, both full-siblings to Predawn. Qualify produced Cualificar (Lope de Vega), a multiple group winner who took the Gr.2 Prix Niel and was multiple Group 1-placed, and the group winner Swing Vote (Shamardal), successful in the Gr.3 Jebel Ali Mile.

Third dam Medicosma (The Minstrel) won twice at three and bred five other winners.

Predawn has a 2-year-old filly by Oasis Dream named Flutterfly, a yearling filly by Sea The Moon and a 2026 filly by Pinatubo.