He was a sympathizer of the reforms of Pope Gregory VII and thus on the side of the latinist column in Dalmatia and Croatia, despite his Slavic (Croat) background.
[2] He is mostly known for founding the monastery of St. Peter in Selo, a location in medieval Poljica, together with his wife on 11 October 1080 during the reign of king Demetrius Zvonimir.
Petar Crni endowed the monastery with land (in Poljica, Split and the island of Brač) and adorned it with art, silver utensils and eucharistic vestments.
[3] Trading included with people from Šibenik, Knin, the surrounding region and with foreign merchants such as the Lombards.
[4] The first four verses are: TAM SORDENTE DOMO PERSPICE QVID SIT OMO / IN REBUS STVLTIS STVDVI NICHIL VTILE MVLTIS / ET DVM UIGVI TERROR IN ORBE FVI/PARVM ADVC DICAM DE MEI CORPORIS V(I) T(A)M In such a perspiring house look at what a man is In the earthly foolishness I tried not to be of use to anyone And while I was rugged, I was fear to the world That is all i can say about my (earthly) life