Why are ethnic identity and religious affiliation closely linked in Croatia?

In Croatia, the close link between ethnic identity and religious affiliation is rooted in historical, cultural, and political developments that have shaped the region for centuries.12

Traditionally, this correlation is defined by the following distinctions:
* Croats are overwhelmingly Roman Catholic and have historically maintained stronger ties to Western cultural influences.1
* Serbs in the region are predominantly Eastern Orthodox.1

This association was significantly reinforced during the 19th-century nationalist movements in the Balkans. During this period, religious practice became a primary marker for national identity; for example, populations in the region practicing Roman Catholicism were increasingly identified as Croats, while those practicing Serbian Orthodoxy were identified as Serbs.2

Furthermore, the legacy of the Ottoman Empire played a crucial role, as it allowed for the coexistence of autonomous religious communities, which helped solidify these distinct identities. In the modern era, the role of religion as a national identifier was further elevated by the collapse of communism, the rise of nationalism during the disintegration of Yugoslavia, and the conflicts of the 1990s.2