Hattusa (also Ḫattuša or Hattusas or Hattusha) was the capital, during two periods, of the Hittite Empire in the late Bronze Age. Its ruins lie near modern Boğazkale, Turkey, (originally Boğazköy) within great loop of the Kızılırmak River (Hittite: Marashantiya; Greek: Halys). Hattusa was added to the UNESCO World Heritage Site list in 1986. The earliest traces of settlement on the site are from the sixth millennium BC during the Chalcolithic period. Toward the end of the 3rd Millenium BC the Hattian people established a settlement on locations that had been occupied even earlier and referred to the site as Hattush. In the 19th and 18th centuries BC, merchants from Assyria, centered at Kanesh (Neša) (modern Kültepe) established a trading post there, setting up in their own separate quarter of the lower city. A carbonized layer apparent in excavations attests to the burning and ruin of the city of Hattusa around 1700 BC. The responsible party appears to have been King Anitta from Kussara, who took credit for the act and erected an inscribed curse for good measure: "Whoever after me becomes king resettles Hattusas, let the Stormgod of the Sky strike him!" though in fact the city was rebuilt afterward, possibly by a son of Anitta. In the first half of the 2nd Millenium BC the Hittite king Labarna moved the capital from Neša to Hattusa and took the name of Hattusili, the "one from Hattusa". After the Kaskians arrived to the kingdom's north, they twice attacked the city and under king Tudhaliya I, the Hittites moved the capital north to Sapinuwa. Under Muwatalli II, they moved south to Tarhuntassa but the king assigned his son, the future Hattusili III as governor over Hattusa. In the mid-13th century BC Hittite ruler Mursili III returned the seat to Hattusa, where the capital remained until the end of the Hittite kingdom in the 12th century BC (KBo 21.15 i 11–12). At its peak, the city covered 1.8 km2 and comprised an inner and outer portion, both surrounded by a massive and still visible course of walls erected during the reign of Suppiluliuma I (1344–1322 BC (short chronology)).