Guillaume de St. Omer

-https://fmg.ac/Projects/MedLands/LATIN%20LORDSHIPS%20IN%20GREECE.ht...

2. GUILLAUME de Saint-Omer (-after 19 Oct 1265). The late 13th century genealogy by Balduinus de Avennis names "Bilas…Wilelmo" as the two sons of "castellano Sancti-Audomari domino Wilelmo…quintus filius Nicolaus" and his wife, adding that Guillaume died childless[953]. In Naples, later in Flanders.

m (before 15 Oct 1256) as her second husband, PERNEL de Lacy, widow of RAOUL [VI] de Tosny, daughter of WALTER de Lacy & his wife [Marguerite de Briouze] (-after 25 Nov 1288).

https://www.wikitree.com/wiki/St_Omer-4