[1] According to the cathedral chapter's list of suffragans, Zosimus was elected bishop in 1259, succeeding Vincent, who died in the previous year.
He continued his predecessor's agricultural activity in order to revive the economy and cultural life of the Diocese of Várad after the first Mongol invasion of Hungary.
[3] Zosimus' episcopal tenure covered the period of tensions between King Béla IV of Hungary and his son Duke Stephen.
In the emerging conflict, the bishop supported the younger king because the territory of the diocese laid in the latter's realm according to the 1262 treaty.
When Béla IV confirmed the last will on 17 October 1265, the king referred to Zosimus as a still living person, who donated the aforementioned estate to the cathedral chapter of Esztergom five days earlier, for being properly cared for during his illness.