21st century BC

Events

2100 BC — Beginning of the Xia Dynasty, the first dynasty and government system in China.
c. 2100–2050 BC — Nanna Ziggurat, Ur (modern Muqaiyir, Iraq) is built.
2091 BC — Beginning of the mythological Patriarchal Age is traditionally set in this year.
2080 BC — Ninth Dynasty wars in Egypt.
2080 BC — First Intermediate Period of Egypt ends. Middle Kingdom starts in Ancient Egypt.
2071 BC — Magh Ithe, first recorded battle in Ireland myths.
2070 BC (disputable) — Yu the Great set up the Xia Dynasty, which isn't verified by archeological findings, some propose the Erlitou culture.
2064–1986 BC — Twin Dynasty wars in Egypt.
c. 2055 BC — End of First Intermediate Period of Egypt (another date is 2040 BC).
c. 2055 BC — Middle Kingdom starts in Ancient Egypt (other date is 2040 BC).
c. 2055 BC — Prince Mentuhotep II from Thebes manages to reunite Ancient Egypt (other date is 2040 BC).
c. 2055 BC — Pharaoh Mentuhotep II starts to rule in Ancient Egypt
2049 BC — Oak trees for Seahenge felled.
c. 2040 BC — End of First Intermediate Period of Egypt. Start of Middle Kingdom. 11th–14th Dynasties.
2040 BC — Pharaoh Merykare died. End of Tenth dynasty of Egypt. Pharaoh Mentuhotep II started to rule. Start of Eleventh Dynasty.
2034–2004 BC — Ur-Amorite wars.
c. 2009–1997 BC — Funerary temple of Mentuhotep III was built. Eleventh Dynasty.
2004 BC — Elamite destruction of Ur.
c. 2004 BC — Pharaoh Mentuhotep II, Eleventh dynasty of Egypt dies.

Ur-Nammu, 3rd dynasty of Ur
Shulgi of Urim
Abraham (perhaps, other datings include 19th century BC, 17th century BC, 16th Century BC, and 15th Century BC)
According to Hindu tradition, lifetime of Rama, the 7th avatar of Vishnu

2100 BC — Earliest extant law code in Mesopotamia, the Code of Ur-Nammu
2037 BC — Emperor Shen Nong makes first (perhaps mythical) tea drink by boiling fresh leaves