What century did Shulgi reign for 48 years?
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).
Ashur-rabi II Aššur-rabi II, inscribed "aš-šur-""-bi", "(the god) Aššur is great," was king of Assyria 1012–972 BC. Despite his lengthy reign (41 years), one of the longest of the Assyrian monarchs, his tenure seems to have been an unhappy one judging by the scanty and laconic references to his setbacks from later sources.