The latter practice, supported by Puffendorf and later by de Vattel, persisted until the mid-19th century, when Denmark dropped the levies for the passage of Danish belts and sunds[9] (cf.
[11] With the arrival of steamships in the 19th century, the ability to navigate along the shortest route became a significant economic factor,[12] spurring development of special regimes for transit, similar to high seas.
[11] A major effort on codification of the legal regime for the straits was made by the Institut de Droit International (IDI) between 1894 and 1912.
[16] Convention on the Territorial Sea and the Contiguous Zone, adopted in 1958 by the UNCLOS I, codified the work of the International Law Commission done since 1949.
[19] Although during the planning of the conference it was declared that it will concentrate on exploitation of the sea beds, in practice it was to large extent driven by the desire of "the United States and the Soviet Union [...] to protect their strategic interests in transiting the oceans, particularly international straits".
[20] As a result of the political compromise, UNCLOS III adopted its "crowning achievement",[21] a new transit passage regime with no previous legal precedents.