Andrew II of Hungary, who died on 21 September 1235, was buried in Egres Abbey, which located in the territory of Benedict's diocese. Benedict became a staunch supporter of Béla IV, who ascended the Hungarian throne. After the death of Primogenitus, Pope Gregory acknowledged his bishopric and confirmed the election (although it was not required at that time). His diocese severely devastated during the Mongol invasion of Hungary in 1241. Güyük Khan invaded Transylvania from the Oituz Pass in March. Benedict gathered his army and marched out to the royal camp at the Sajó river, but a vanguard of Mongol marauders clashed with his army near Eger. Benedict defeated them, but another Mongol army forced him to withdraw to his episcopal seat, Várad. As one of his canons, Roger of Torre Maggiore preserved the events in his account "Carmen Miserabile", the town was captured and devastated by the Mongols. Benedict gathered the remnants of his episcopal army and fled his diocese in order to seek refuge beyond the river Danube. Benedict never returned to the Diocese of Várad.