Question: What century did Shulgi reign for 48 years?

Context paragraphs:
Muhammad Imaaduddeen IV: Muhammad Imaaduddeen IV was the sultan of the Maldives from 1835 to 1882.  He ruled for 48 years, 4 months, and 28 days, making his reign the longest ever in the Maldives.

Jean Enersen: Jean Stanislaw Enersen (born June 16, 1944) is an American journalist who worked for 48 years at KING-TV in Seattle.  As an anchor for 42 years, she is the first and longest-standing local female anchor in the country.  She retired from full-time duties at KING in the summer of 2014, and accepted a retirement buy-out by Tegna, formerly Gannett, in April 2016.  She will no longer be seen on KING-TV, after 48 years with the station.

Marquis Gòng of Cai: Marquis Gòng of Cai (蔡共侯) (?  - 760 BC), born as Ji Xīng (姬興), was the ninth ruler of the State of Cai from 761 BC to 760 BC.  He was the only known son of Marquis Yi of Cai (蔡夷侯), his predecessor.  His reign only lasted for 2 years, which seem reasonable since his father's reign was 48 years making him an old man by the time he became Marquis.  He was succeeded by his son.

Babylonian calendar: The Babylonian calendar was a lunisolar calendar with years consisting of 12 lunar months, each beginning when a new crescent moon was first sighted low on the western horizon at sunset, plus an intercalary month inserted as needed by decree.  The calendar is based on a Sumerian (Ur III) predecessor preserved in the Umma calendar of Shulgi (c. 21st century BC).

Wanli Emperor: The Wanli Emperor (; 4 September 1563 – 18 August 1620), personal name Zhu Yijun (), was the 13th emperor of the Ming dynasty of China.  "Wanli", the era name of his reign, literally means "ten thousand calendars".  He was the third son of the Longqing Emperor.  His reign of 48 years (1572-1620) was the longest among all the Ming dynasty emperors and it witnessed the steady decline of the dynasty.

Darejan Dadiani: Darejan Dadiani (Georgian: დარეჯანი ), also known as Daria (დარია; Russian: Дарья Георгиевна , "Darya Georgyevna") (20 July 1738 – 8 November 1807), was Queen Consort of Kakheti, and later Kartli-Kakheti in Eastern Georgia, as the third wife of King Erekle II (also known as Heraclius II).  She was a daughter of Katsia-Giorgi Dadiani, a member of the princely house of Mingrelia.  Darajan married Heraclius in 1750 and their marriage lasted 48 years until his death in 1798; the union produced 23 children.  In the final years of her husband's reign, Darejan exerted significant influence on politics and court affairs.  She was skeptical of the pro-Russian policies of Heraclius II and his successor, her step-son, George XII, whose progeny she tried to prevent from succeeding to the throne of Georgia.  After the Russian annexation of Georgia, Queen Dowager Darejan was deported to Russia proper in 1803.  She died in St. Petersburg at the age of 69 and was buried at the Alexander Nevsky Lavra.

Hudjefa I: Hudjefa I is the cartouche name and pseudonym of a king (pharaoh) who is said to have ruled during the Ancient Egyptian 2nd dynasty.  The exact length of his reign is unknown since the Turin canon gave him a reign of 11 years while the ancient Greek historian Manetho suggested that the pharaoh ruled for 48 years.  Egyptologists consider both statements as exaggerations and generally consider that Hudjefa I only ruled for a maximum of 2 years.

Shulgi: Shulgi ( Šulgi, formerly read as Dungi) of Ur was the second king of the "Sumerian Renaissance" in the Third Dynasty of Ur.  He reigned for 48 years, from c. 2029 – 1982 BC (short chronology).  His accomplishments include the completion of construction of the Great Ziggurat of Ur, begun by his father Ur-Nammu.

Miss International 2008: Miss International 2008, the 48th Miss International pageant, was held on November 8, 2008 at The Venetian Macao in Macau，the presenters are Dodo Cheng, Eric Tsang, Astrid Chan.  63 contestants from all over the world competed for the crown, marking the biggest turnout in the 48 years of the pageant, surpassing the previous of 61 during last year pageant.  The contestants also paid a visit to Hong Kong, Tokyo.  Miss International 2007, Priscila Perales of Mexico, crowned her successor Alejandra Andreu of Spain as the new Miss International.

Marquis Xi of Cai: Marquis Xi of Cai (蔡釐侯) (died 761 BC), given name Suǒshi (所事), was the eight ruler of the State of Cai from 809 BC to 761 BC.  He was the only known son of Marquis Yi of Cai (蔡夷侯), his predecessor.  His reign lasted for 48 years, the longest reign in Cai history.  He was succeeded by his son.

Supporting paragraphs: Babylonian calendar Shulgi
Answer: 21st century BC