Julius was born into the gens (clan) Básztély, which elevated into the social status of nobility due to military merits and successes of his father, Reynold II.
His mother was Reynold's second wife, an unidentified sister of noble Nicholas Vecse de Putnok from the gens Rátót.
Presumably, he built the castle of Csicsva in Zemplén County (present-day part of Sedliská in Slovakia) in the early 1300s, but it is also possible that the fort was constructed already during his father's time.
Belonging to his escort, Julius was present in Kassa (today Košice, Slovakia) on 5 September 1311, when the powerful oligarch and Charles' mainstay Amadeus Aba was assassinated.
Julius remained a loyal partisan of Charles during the conflict, as the king confirmed his donation letter to his servant on 14 June 1312, one day before the Battle of Rozgony.