Petrich (Bulgarian: Петрич) is a town in Blagoevgrad Province in southwestern Bulgaria, located at the foot of the Belasitsa mountain. Petrich is famous for the surrounding mountain landscapes. As of 2005, the town has 35,134 inhabitants. Petrich was included in the territory of the Bulgarian State during the reign of Knyaz Boris I (852-889). During the Middle Ages it was a Bulgarian fortress of big importance during Tsar Samuil's wars (997-1014) with Byzantium. During the Ottoman rule, it was initially part of the Serez sandjak of the Rumeli vilayet. After that it became a kaza of the Serez sandjak in the Selanik vilayet, before being included in Bulgaria following the Balkan Wars in 1913. The town was briefly occupied by the Greek army in 1925.