The submission acknowledged the improved relations between the once war-torn Balkan nation and the EU, but it also marks just the start of an arduous, years-long negotiation process that will determine if Bosnia gains full membership in the bloc.

In recent years, the EU has tried to engage Bosnia in talks about joining its ranks in hopes that it would prompt political stability in the former Yugoslav republic and greater cooperation in the region. Last year, EU foreign ministers cleared a path for Bosnia’s eventual membership in the EU by agreeing to an economic and trade pact in exchange for a pledge by Bosnian leaders to enforce political reforms.

But the nation is still plagued by deep ethnic and political divides that sparked a three-year conflict in the early 1990s that killed 100,000. Plus, its admission to the EU could be derailed if Milorad Dodik, the leader of the autonomous Bosnian-Serb region of Republika Srpska who’s wary of EU membership, makes good on a threat to hold an independence referendum.

Despite Bosnia’s impending uphill battle, EU foreign policy chief Federica Mogherini said Monday that she saw promise in the nation’s application. “At a time when the union is questioned from within, seeing that with our immediate neighbors there is such an energy and willingness to join and work hard to adapt their countries, society, economy, institutions, systems to the European standards, gives us the sense of responsibility we have also towards our European Union citizenship.”

The most recent country to join the EU was Croatia, which became the 28th member in 2013.