For a year and a half before the expedition Niebuhr studied mathematics, cartography and navigational astronomy under Tobias Mayer (1723–1762), one of the premier astronomers of the 18th century, and the author of the Lunar Distance Method for determining longitude.

[2][3] His transcriptions were especially useful to Georg Friedrich Grotefend, who made the first correct decipherments of Old Persian cuneiform:[4] He also visited the ruins of Babylon (making many important sketches), Baghdad, Mosul, and Aleppo.

After a visit to Cyprus, he made a tour through Palestine, crossed the Taurus Mountains to Bursa, reached Constantinople in February 1767 and finally arrived in Copenhagen in the following November.

In summary, Niebuhr's maps, charts and plans constitute the greatest single addition to the cartography of the region that was produced through field research and published in the 18th century.

[7] In 1773, Niebuhr married Christiane Sophia Blumenberg, the daughter of the crown physician, and for some years he held a post in the Danish military service, which enabled him to remain in Copenhagen.

Niebuhr's first book, Beschreibung von Arabien, was published in Copenhagen in 1772, the Danish government providing subsidies for the engraving and printing of its numerous illustrations.

His accurate copies of the trilingual inscriptions gave Orientalists the key to finally crack the cuneiform code, leading to the discovery of Old Persian, Akkadian, and Sumerian.

[8] The third volume of the Reisebeschreibung, also based on materials from the expedition, was not published till 1837, long after Niebuhr's death, under the editorship of his daughter and his assistant, Johan Nicolaus Gloyer.

Niebuhr also contributed papers on the interior of Africa, the political and military condition of the Ottoman Empire, and other subjects to a German periodical, the Deutsches Museum.

In addition, he edited and published the work of his friend Peter Forsskål, the naturalist on the Arabian expedition, under the titles Descriptiones animalium, Flora Aegyptiaco-Arabica and Icones rerum naturalium (Copenhagen, 1775 and 1776).

And in the same year the Danish Ministry of Foreign Affairs had planned a series of cultural events based on the Expedition and Niebuhr's work that would take place in Ankara, Cairo, Damascus, Beirut, Tehran, and Yemen.