[1] Nikon was on the throne of the Serbian Church during the reign of Stefan Lazarević and after.
The earliest mention of this Serbian hierarch was noted in 1419 in the "Praise to Prince Lazar" written by Antonije Rafail, a writer of Greek origin who fled to Serbia from the Ottoman Empire.
In the spring of 1426, at a state Sabor held in Srebrenica, Stefan selected and appointed Đurađ Branković as his successor.
The following year (1427), the new ruler of Serbia, Đurađ Branković, forbade Serbian Patriarch Nikon to attend the Council of Florence on 6 July 1439 on the grounds that he mistrusted the motives of that council and questioned the principle of papal supremacy.
[citation needed] The last mention of Patriarch Nikon is from 1435 in a record of the manuscript Triodion transcribed by Deacon Arsenije.