Definition: In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Input: Passage: Pavle Bakic had a timar, as did his father, and held great estates around Vencac in Sumadija called "Bakic's land". He was highly viewed of by the Ottoman Empire, and had the rights to collect taxes (kharaj) from his people. In talks with Pal Tomori and Louis II of Hungary, he left his land with his family, five brothers (including Petar Bakic), and a great number of Serbs, into Hungary, and in return he received the town of Lak among other estates. With his forces he participated in the Battle of Mohacs in 1526. When the succession war between Ferdinand I and John Zapolya started, he took the side of Zapolya. After the defeat of Zapolya in the Battle of Tokaj in 1527, he sided with Ferdinand and would stay faithful to him for the rest of his life. In 1528, Ferdinand confirmed Bakic and his brothers' holdings and appointed him the captain of the Serbian infantry, cavalry and river forces. In the defence of Vienna in 1529, Bakic was an important aspect with his cavalry. In charters of 1534, Ferdinand again confirmed Bakic and his brothers' holdings (Lak, Gyor, Szombathely, Hedervar and all estates that were part of these towns). The fortress of Gyor was administered by his Hungarian ally Count Gyorgy Cseszneky. A charter dated September 20, 1537, titles him as Despot and called all Serbs to join Bakic as the Serbian Despot. Attempts made by King Ferdinand to push the Ottomans out of Slavonia, with the use of Pavle, were not successful. Bakic did not manage to liberate Osijek from the Ottomans, he then retreated to akovo, where he at Gorjani, in a battle against the Ottomans, died (1537). Mehmed-pasa sent his son with the head of Bakic to Istanbul.
Link Information: Ferdinand I () (10 March 1503 25 July 1564) was Holy Roman Emperor from 1556, king of Bohemia and Royal Hungary from 1526, and king of Croatia from 1527 until his death in 1564. Question: How long had Ferdinand I been in power when he defeated Zapolya?
Output:
Answer: 1