His date of birth is unknown, for the first time his name was written in Krakow city documents in 1483. He married the daughter of another noble krakowian, Szczęsna Morsztynowna. He is most famous as a “banker of three kings“: Jan Olbracht, Aleksandr and Sigismund the Old.
In 1493 he bought a house at Main Market Square 43(now famous as Palace Bonerowski), in 1498 he became an alderman and in 1514 he was ennobled. Thanks to the numerous financial operations he managed to buy villages Balice and Szczygłów, castle in Ogrodzieniec, houses in Krakow, Lviv and Poznań. He was a castellan of Żarnów, Biecz and Sącz, a foreman of Rabka and a stewart of Krakow saltworks. He has also established a paper mill in Bonarka and was producing a high quality paper. He was famous as a patron of art.
He had his own chapel in St Mary’s Basilica which was decorated by Hans Suess.
Jan was also incharge at some of Wawel castle reconstructions.
King Sigismund the Old admired Jan Boner and to show his respect was annually visiting his house on Jan’s name day.
Jan had three brothers: Jakub, Andrzej and Fryderyk. Jakub’s name is quite infamous because of his financial manipulations in Nuremberg where he was representing the Boner financial company. Veit Stoss, mostly famous for creating the altarpiece in St Mary’s Basilica, after finishing his work in Krakow came back to his home town, Nuremberg, and wanted to invest his earnings in Boner’s company. But Jacub convinced him to locate his money in Jens Starzedel’s bank, which owed Boner a huge amount of money. When Veit Stoss followed his advice Jacub immediately picked up the dept from Starzedel’s bank which caused its bankruptcy. Veit Stoss lost all the money he earned in Krakow. Desperate to get his money back he forged Jakub’s signature on a bill of exchange , for which he was branded on both of his cheeks as a fraud and prohibited from leaving Nuremberg. Jakub came back to Krakow in 1512 and bought a house from his brother at Main Market Square 9, but soon after this he moved to Wroclaw where he died in 1517.
Andrzej Boner, Jan’s and Jakub’s brother, was the only one who did not do banking. He was a poet and a publisher. The fourth brother, Fryderyk, was managing a mint in Głogów owned by then prince Sigismund Jegiellończyk, who later became a king Sigismund the Old.