Namur is out of Sambre et Meuse (Daiwa Major), a triple winner who was Group 3-placed, and is one of four winners from four runners. Sambre et Meuse is also the dam of Ravel (Kitasan Black), a Group 2 winner at two who was Group 1-placed, and Westerwald (Novellist), Group 3-placed in Japan.

The second dam Vite Marcher (French Deputy) was a winner and is the dam of Marche Lorraine (Orfevre), winner of the Grade 1 Breeders' Cup Distaff in 2021, the dual Listed winner in Japan Badenweiler (Duramente), the Group 3-placed Avenir Marcher (Deep Impact) and the maiden winner Marcha Real (Real Impact). She is a half-sister to Triumph March (Special Week), a Listed winner who was Group 2-placed, and to the Listed-placed Imperial March (Neo Universe).

Third dam Kyoei March (Dancing Brave) won five Listed races and the Gr.1 Oka Sho in 1997, and was second to Taiki Shuttle (Devil's Bag) in the Gr.1 Mile Championship that year.

Sambre et Meuse has a 2-year-old filly, Arsenaal (Epiphaneia), a winner on debut, and a yearling filly by Bricks and Mortar. She was barren to Harbinger in 2023.