Which Hittite capital's archives preserved Bronze Age diplomacy?

Hattusa, in central Turkey, where excavation found tens of thousands of clay tablets - the diplomatic and administrative archive of an empire nobody knew existed until the nineteenth century. The Hittites appear in the Bible and had otherwise vanished from history entirely.

The archive contains the oldest surviving peace treaty in the world, between Hattusili III and Ramesses II after the battle of Kadesh, around 1259 BC. Both sides claimed to have won and both texts survive - the Egyptian version carved on temple walls, the Hittite in cuneiform on a tablet - which makes it the earliest case where a historian can read two states describing the same event and lying differently. A copy hangs at the United Nations.

Deciphering the language produced a shock. Hittite turned out to be Indo-European - related to Greek, Latin, Sanskrit, English - and much older than anything else in the family, which forced a rewrite of where those languages came from. It also confirmed a prediction: Saussure had argued in 1879 that the ancestral language must have contained sounds that had disappeared everywhere, purely from the shape of the evidence, and Hittite turned out to still have them.