1540 – On his father’s death, as an infant he was crowned as the new King of Hungary.
1541 – Sultan Sulayman I invaded Hungary on the excuse of protecting John’s interest. John and her mother Isabel received the principality of Transylvania with a monk named George Martinuzzi as his guardian.
1551 – Transylvania was reunited once again with Hungary. The deposition of John and Isabel was acquired by Martinuzzi, distinguishing Ferdinand as the king who had him assassinated.
1556 – The diet of Transylvania was recalled on the force of Sulayman.
1562 – John was recognized as the ruler of Transylvania right after Ferdinand made peace with Sulayman, but Hungary remain divided into three states.
1564 – It was under John II that the Transylvanian diet adopted. His successor as the prince of Transylvania was Stephen Báthory, with Calvanism as the state of religion.