Peter Kresimir was born as one of two children to Croatian king Stephen I and his wife Hicela (or Mary), who was possibly of Venetian descent.
Before succeeding the throne, Krešimir had been under suspicion of murdering his brother Gojslav (or Častimir) in order to secure the throne for himself.
Eventually, the church had decided to interfere, and Pope Alexander II had sent one of his delegates to inquire about the death of Gojslav.
Only after the prince and twelve Croatian župans had taken oath that he did not kill his brother, had the Pope given his support to his claim and symbolically restored the royal power to Kresimir.
Raised in Venice, Kresimir had succeeded his father Stephen I upon his death in 1058 and had been crowned the next year.
It is not known where his coronation took place, but some historians suggest Biograd as a possibility.
From the outset, he had continued the policies of his father, but had immediately been requested by Pope Nicholas II, first in 1059 and then in 1060, to reform the Croatian church in accordance with the Roman rite.
This is especially significant to the papacy in the aftermath of the East-West Schism of 1054, when a papal ally in the Balkans is a necessity.
Kresimir and the upper nobility lend their support to the pope and the church of Rome.
The lower nobility and the peasantry, however, are far less well-disposed to reforms.
The Croatian priesthood is aligned towards Greek orthodox orientalism, including having long beards and marrying.
More so, the ecclesiastical service is likely practiced in the native Slavonic (Glagolitic), whereas the pope demands practice in Latin.
This had caused a rebellion of the clergy led by a priest named Vuk against celibacy and the Latin liturgy in 1063, but they are proclaimed heretical at a synod of 1064 and excommunicated, a decision that Kresimir supports.
He harshly quellsall opposition and sustains a firm alignment towards western Romanism, with the intent of more fully integrating the Dalmatian populace into his realm.
In turn, he can then use them to balance the power caused by the growing feudal class.
By the end of Kresimir's reign, feudalism will have made permanent inroads into Croatian society and Dalmatia will be permanently associated with the Croatian state.
