 It appears from the Latin original spelling of their name Gastoldus which is a variation of "castaldius" that they had been close to the Grand Dukes and that their function was to oversee ducal demesne.Most power family gained during the reign of Casimir Jagiellon.The castaldius of Vytautas, Andrius Goštautas might have been a voivode of Vilnius and Kreva, and father of Jonas, appears to have been the precursor of the family growth.