Hattusa (URUḪa-at-tu-ša 𒌷𒄩𒀜𒌅𒊭; Ḫattuša, near modern Boğazkale (formerly Boğazköy), Turkey) was the capital of the Hittite Empire in the late Bronze Age. The region is set in a loop of the Kızıl River (Marashantiya in Hittite sources and Halys in Classical Antiquity) in central Anatolia.
Hattusa was added to the UNESCO World Heritage list in 1986.
Before 2000 BC, a settlement of the apparently indigenous Hatti people was established on sites that had been occupied even earlier. The earliest traces of settlement on the site is from the sixth millennium BC. In the 19th and 18th centuries BC, merchants from Assur in Assyria established a trading post here, setting up in their own separate quarter of the city. The center of their trade network was located in Kanesh (Neša) (modern Kültepe). Business dealings required record-keeping: the trade network from Assur introduced writing to Hattusa, in the form of cuneiform.
A carbonized layer in the excavations records the burning and ruin of the city of Hattusa around 1700 BC. The responsible party appears to have been King Anitta from Kushar (a city possibly to be identified with Alişar), who took credit for the act and erected an inscribed curse for good measure:
At night I took the city by force; I have sown weeds in its place. Should any king after me attempt to resettle Hattush, may the Weathergod of Heaven strike him down.
After the Kaskas arrived to the kingdom's north, they twice attacked the city to the point where the kings had to move the royal seat to another city. Under Tudhaliya I, the Hittites moved north to Sapinuwa, returning later. Under Muwatalli II, they moved south to Tarhuntassa but assigned Hattusili III as governor over Hattusa. Mursili III returned the seat to Hattusa, where the kings remained until the end of the Hittites.
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 (circa 1344 - 1322 BC (short chronology)). The inner city covered an area of some 0.8 km² and was occupied by a citadel with large administrative buildings and temples.
To the south lay an outer city of about 1 km², with elaborate gateways decorated with reliefs showing warriors, lions, and sphinxes. Four temples were located here, each set around a porticoed courtyard, together with secular buildings and residential structures. Outside the walls are cemeteries, most of which contain cremation burials. Modern estimates put the population of the city between 40,000 to 50,000 at the peak. In the early period the inner city housed a third that number. The dwelling houses which were built with timber and mud bricks have vanished from the site leaving only the stone-built-walls of temples and palaces.
The city was destroyed, together with the Hittite state itself, around 1200 BC, as part of the Bronze Age collapse. The site was subsequently abandoned until 800 BC, when a modest Phrygian settlement appeared in the area.
Although the 30,000 or so clay tablets recovered from Hattusa form the main corpus of Hittite literature, archives have since appeared at other centers in Anatolia, such as Tabigga (Maşat Höyük) and at Sapinuwa (Ortaköy). They are now divided between the archaeological museums of Ankara and Istanbul.