In documents from 1501, Staikos, the ruler of Vlachia, is recorded as being the new founder of the Monastery. This began an important period of sponsorship by leaders of Vlachia and Moldavia, who supported the Athonite communities particularly during the 16th century, and to a large degree shaped the present day appearance of the structures within the Monastery complex.
Another important sponsor was the Moldavian ruler Neagoe Basarab Kraioveskou, who is also known for his close relationship with the hieromonk Nifon and his work at the Dionysios Monastery. In his Romanian biography, he is characterised as the founder of both the Pantokratoros and Iviron monasteries.
Vasilieos Barski refers to the third founder as ‘Barboulos’; however, no evidence has been found which connects this name with any of the similarly-named rulers of the period. Gabriel Totousianos, the great Moldavian Treasurer and Chancellor (1516-1523, 1539-1541), funded the repairs to the Byzantine aqueduct in 1536/7.