According to the Illuminated Chronicle, Ladislaus, who laid on his deathbed, sent Palatine Peter and Marcellus to Poland to negotiate the duke's deputy Sieciech in the summer of 1095.
[1] Another chapter of the chronicle styles Marcellus as "sanctus", which referred to his pious nature and exemplary saintly way of life despite his young age, as medievalist László Koszta argued.
Koszta considered it reflects to the situation when the charter was written, thus Marcellus already functioned as Archbishop of Esztergom in 1118 (his predecessor Lawrence died approximately two years ago).
It confirms that Marcellus had also participated in the royal campaign against the province, taking advantage of the temporary absence of the Venetian fleet from the Adriatic Sea.
[4] As his successor Felician was referred to as archbishop by a charter dated between around the years 1125 and 1128, Marcellus possibly died not long after his last appearance in contemporary documents.