21st century BC
The 21st century BC lasted from the year 2100 BC to 2001 BC.
Events
Image:Sumerian_Cylinder_Seal_of_King_Ur-Nammu.jpg|thumb|Ur-Nammu bestows governorship on Ḫašḫamer, patesi of Iškun-Sin.All dates from this long ago should be regarded as either approximate or conjectural; there are no absolute dates for this time period.
- – The First Intermediate Period of Egypt, a period of decline in Egyptian central power.
- – The Third Dynasty of Ur. The Ziggurat of Ur is built. Administrative power in Ur is pushed far, with an Ensi, an appointed civil servant, at the head of the constituencies. A meticulous and finicky bureaucracy manages, counts and controls the whole administration, which is as much concerned with the economy as with war or the service of the gods. The weight of such an administration arguably contributes to the collapse of the empire. Finally, the Elamites sack Ur and the third dynasty comes to an end.
- :
- * Epic poetry is written in the Sumerian language, including the Epic of Gilgamesh.
- * In Chalcolithic Europe, the two circles of bluestones that form the inner part of Stonehenge are erected.
- * Shahr-e Sukhteh, "The Burnt City" in Persia, is abandoned.
- : The beginning of the Middle Minoan civilization in Crete. Bronze metallurgy and the potter's wheel are introduced, as are Cretan hieroglyphs.
- – The Sintashta culture emerges in the northern Eurasian Steppe.
- – Yu the Great establishes the Xia dynasty in China.
- – The beginning of the Middle Kerma culture in Upper Nubia.
- Late spring 2049 BC – Seahenge is built in Britain.
- – Mentuhotep II, ruler of the Eleventh Dynasty of Egypt in Thebes, completes the reunification of Egypt following his victory over the pharaohs of Herakleopolis, which marks the beginning of the Middle Kingdom.
- – The earliest bronze age artifacts in Southeast Asia found in the Ban Chiang site in modern-day Thailand indicate the absence of a militaristic or urbanized state.