evidence: The maritime boundary between Croatia and Slovenia in the Piran Bay has been disputed since the dissolution of the former Yugoslavia in 1991. Because Slovenia has a relatively small coast, its territorial waters are boxed off from international waters by Croatian and Italian territorial waters, and Slovenia seeks a direct corridor from its own territorial waters to international waters. In addition, there are several disputed aspects of the land boundary between the two states. The dispute has had implications with respect to Croatia’s bid to join the European Union as Slovenia, a member of the European Union, blocked Croatia’s accession talk for several years out of a concern that the accession process could prejudge a solution to the boundary dispute between the two countries. In November 2009, however, Croatia and Slovenia signed a bilateral agreement submitting the dispute to arbitration before a five-member ad hoc tribunal, and Croatia signed the European Union-accession treaty in December 2011. Under Article 4(b) of the arbitration treaty, the tribunal is to apply principles of "international law, equity and the principle of good neighbourly relations in order to achieve a fair and just result by taking into account all relevant circumstances."