Romania and Bulgaria became full members of the Schengen zone on Wednesday, expanding the borderless area to 29 members and ending a 13-year wait for the two eastern European countries.

The expansion, made possible when Austria and other members dropped their objections to the former communist countries joining, officially took place at midnight on January 1, marked by ceremonies at various border posts.

Romania and Bulgaria, both members of the European Union since 2007, were partially included in the Schengen zone in March, eliminating border checks at ports and airports.

But Austria had threatened to veto their full entry over migration concerns, which meant that controls still applied at land border crossings.

Vienna backed off its veto threat in December after the three countries reached a deal on a “border protection package”, clearing the way for Romania and Bulgaria, two of the EU’s poorest countries, to join Schengen.