In science, the 20s saw the manufacture ofpens and metal writing tools in Rome. Major disasters of this decade include a fire inRome, and the collapse of a poorly builtamphitheatre inFidenae, which killed 20,000 of the 50,000 spectators. In 27,Christianity was born as aJewish sect inJerusalem.Geographica, an encyclopedia of geographical knowledge created byStrabo, was finished no later than AD 23.
Manning (2008) tentatively estimates the world population in AD 20 as 246 million.
Due to lack of reliable demographic data, estimates of the world population in the 1st century vary wildly, with estimates for AD 1 varying from 150[1] to 300[2] million. Demographers typically do not attempt to estimate most specific years in antiquity, instead giving approximate numbers for round years such as AD 1 or AD 200. However, attempts at reconstructing the world population in more specific years have been made, with Manning (2008) tentatively estimating the world population in AD 20 as 246 million.[3]
EmperorTiberius' sonDrusus Julius Caesar dies.[8] From that point forward, he seems to lose interest in the Empire and occupies himself with the pursuit of pleasure.
July – After being under siege for two months, about 19,000 insurgents underLiu Xiu defeat 450,000 of Wang Mang's troops in theBattle of Kunyang, ushering in the fall of Wang Mang's Xin dynasty and restoration of the Han dynasty.[11]
October 6 – Emperor Liu Xuan's forces kill Wang Mang at the end of a three-day siege.
The factual accuracy of part of this article isdisputed. The dispute is aboutAt least if quoted correctlyhere Tacitus 4.14 says this event took place in AD 23.. Please help to ensure that disputed statements arereliably sourced. See the relevant discussion on the [[Talk:20s#At least if quoted correctlyhere Tacitus 4.14 says this event took place in AD 23.|talk page]].(July 2024) (Learn how and when to remove this message)
In theKingdom of Silla, which compromises most of the eastern Korean peninsula,Yuri of theHouse of Park becomes the new monarch (thechachaung). King Yuri takes the throne at the capital,Seorabeo (now Gyeongju in South Korea) upon the death of his father,King Namhae.
^Haub (1995): "By 1 A.D., the world may have held about 300 million people. One estimate of the population of the Roman Empire, from Spain to Asia Minor, in 14 A.D. is 45 million. However, other historians set the figure twice as high, suggesting how imprecise population estimates of early historical periods can be."
^Alison E. Cooley,The Cambridge Manual of Latin Epigraphy (Cambridge: University Press, 2012), p. 459
^Jacobo Rodríguez Garrido, "Imperial Legislation Concerning Junian Latins: From Tiberius to the Severan Dynasty," inJunian Latinity in the Roman Empire, Volume 1: History, Law, Literature, Edinburgh Studies in Ancient Slavery (Edinburgh University Press, 2023), p. 106.
^Kang-i Sun Chang; Stephen Owen, eds. (2010).The Cambridge history of Chinese literature. Cambridge, UK: Cambridge University Press.ISBN978-0-521-11677-0.OCLC410227423.
