Fleamont was the later name of a wizarding family who ruled over the archipelago of Caligon. They were originally known as Flamen, a branch of the Actoria gens. During their early years, the Flamens produced many of Caligon's major priests, earning them the eponymous cognomen.

A branch of the Flamens ascended to the kingship of Caligon in what came to be known as the Second Diarchy, sharing the throne with the Pictor branch of the Actorii. The subsequent marriages and adoptions between the two families later led to the creation of the historiographical term "Pictor-Flamenian dynasty" to refer to the period in which the Kingdom of Caligon was ruled by the gens Actoria. Eventually, the extinction of the Pictor branch led to the ascension of the Flamens to the sole kingship, ending the diarchy and restoring the monarchy. They gradually lost interest in ruling as kings of Caligon, and by the early 20th century, the islands were all but abandoned. By this time, the family was known as Fleamont.

Livia Fleamont, the mother of Henry Potter and last to bear the surname, asked on her deathbed for him to preserve her maiden name so it would not die out. Henry honoured her request by naming his son Fleamont Potter. With her death, the possessions of the Fleamonts passed on to the Potter family, including kingship over the islands of Caligon.