Metropolitan is one of two winners out of the unraced Alianza (Halling), a half-sister to the winner Boater (Helmet), runner-up in the Listed Marygate S.

The second dam Cercle D'Amour (Storm Cat) has produced four winners. She is a full sister to Royal Tigress, winner of the Leopardstown 1000 Guineas Trial, then a Listed race, and dam of the stakes winner Ol Donyo and of Tiger Ride (Candy Ride), who won the Grade 3 Pin Oak Valley View S. and was second in the Beldame S., then a Grade 1. Her half-brothers include Warm Heart (Diesis), winner of the Norfolk S., then a Group 3, and second in the Gr.1 Prix Morny, and Miguel Cervantes (Danzig), winner of the Listed Doncaster S. and a sire.

The third dam Warm Mood (Alydar) won five times.

Alianza has a 2-year-old colt by Elarqam and a yearling colt by Romanised.