Both Izsép and John participated in the Battle of Mohi on 11 April 1241, where the Mongol invaders measured heavy defeat on the Hungarian royal army. Both of them fought under the banner of Coloman. While Izsép was killed in the battle, John managed to survive, despite that his left leg was pierced by a spear. John inherited his father's possessions in Somogy County, including Bő – the eponymous estate – with its clan monastery, half of Magyari (today Buzsák) and a portion of Gyugy with accessories, which laid south to Somogyvár. John also owned portions in the nearby villages Szentmárton (today part of Mezőcsokonya) and Bodrog. As a daughters' quarter, John handed over both properties to his unidentified sister. John sold the land Terebezd and the right of patronage over the Bő monastery to vice-judge royal Nicholas Tengerdi in 1257.