According to historian Mór Wertner, Grab was a member of the gens (clan) Tibold of German origin, which settled down in Hungary during the reign of Géza, Grand Prince of the Hungarians.
By the late 1080s, he was elevated into the position of ispán of Somogy County, where the majority of his clan's landholdings laid.
It is possible that the newly founded diocese was granted lands and estates from the territory of Somogy County too (perhaps Dubrava forest, for instance), which indicates Grab's presence as the only ispán among the prelates and court officials during the act.
[3] The name of ispán Grab without seat appears in a non-authentic charter with the date 1093, which narrates a border dispute between the Archdiocese of Kalocsa and the Diocese of Pécs.
[4] Around 1093 or 1094, Grab founded a Benedictine monastery in Garáb in Syrmia County (present-day Grabovo, Serbia), dedicated to Margaret the Virgin.