Egidius (also Giles) was born into the gens (clan) Smaragd, a kindred from the Kingdom of France, which had settled down in Hungary in the middle of the 12th century.
[3] Historians György Györffy and Gergely Buzás considered Egidius is identical with that namesake noble, who held court positions during the reigns of Béla III then Emeric.
In this capacity, he processed demarcation of boundaries for those estates, which members of the gens Héder donated to the Szentgotthárd Abbey, according to a royal charter from 1198.
[6] At an unknown time, Egidius judged over a trial by ordeal in the church of Buda between certain Ruthenian (Russian) merchants and the locals of Szalonta.
[2] Brothers Egidius and Smaragd established a Premonstratensian monastery dedicated to Saint John the Baptist in their ancient estate Zsámbék around 1220.