How did an independent Croatian state develop in the 9th century?

In the 9th century, an independent Croatian state emerged with its political center established in northern Dalmatia. This development followed the arrival of Slavs in the western Balkans during the 6th and 7th centuries, where they settled on Byzantine territory and integrated with the local Latinized population.1

As the state formed, it adopted the Roman Catholic Church while maintaining a Slavonic liturgy. Over time, this nascent state expanded its reach to incorporate Croatia proper and Slavonia, eventually evolving into a significant military power under the leadership of King Tomislav, who reigned from approximately 910 to 928.1