Gilét (or Gyleth) was born into the gens (clan) Smaragd, an illustrious noble family of French origin.
[1] Gilét (I) had two brothers, Smaragd (III), who was Archbishop of Kalocsa and Aynard, ancestor of the clan's Ajnárdfi (Kükei, Atyai and Veér) branch.
[3] Similarly to his brother, Gilét entered the service of Queen Maria Laskarina, the consort of King Béla IV of Hungary.
[3] Gilét and his brothers requested Béla IV in 1258 in order to confirm their ancestors' donations in favor of the Premonstratensian monastery of Zsámbék.
His another son Nicholas (II) – who was ispán of Somogy County from 1319 to 1324[6] – married Clara, the daughter of Demetrius Nekcsei.