Gallus Anonymus, an author of Gesta principum Polonorum written in the early 12th century, put Mieszko third in order, among his brother.
Gesta Danorum | Gesta principum Polonorum | Gesta Hammaburgensis Ecclesiae Pontificum | Mercito Gesta | Gesta Hunnorum et Hungarorum |
Selencia is mentioned twice in the first book of Gallus Anonymus' Gesta principum Polonorum (The Poles' princes' deeds), a chronicle composed in Piast Poland between 1112 and 1118 to glorify the Piast dynasty in general, and the contemporary Piast ruler Boleslaw III Wrymouth in particular.