Custom and its Revival in Transnational Law

39 Pages Posted: 7 May 2014

See all articles by Jan Hendrik Dalhuisen

Jan Hendrik Dalhuisen

King’s College London; University of California, Berkeley; Catolica Global School of Law Lisbon

Date Written: May 6, 2014


Traditionally, custom was considered an autonomous source of law, similar to legislation and case law, but its force was weakened in the 19th century under the influence of modern sovereignty notions and the idea that law could only emanate from states. This weakening had a particular effect in private law, which became domestic and statist, even in respect of international transactions. This change of perception also had an effect on public international law, whose authority suffered as a consequence as well. In private law, the result was the elimination of the force of all immanent law, especially custom but also of general principle. Globalization and the consequent transnationalisation of private law which led in commerce and finance to the re-emergence of a modern law merchant or new lex mercatoria, gave custom, however, a reinvigorated role as an independent source of law, although it still competes with other sources of law, including statist laws of a private or regulatory nature. This leads to a hierarchy of norms which may be seen today as the essence of the new lex mercatoria.

Suggested Citation

Dalhuisen, Jan Hendrik, Custom and its Revival in Transnational Law (May 6, 2014). Duke Journal of Comparative & International Law, Vol. 18, No. 339, 2008, Available at SSRN: or

Jan Hendrik Dalhuisen (Contact Author)

King’s College London ( email )


University of California, Berkeley ( email )

Berkeley, CA
United States

Catolica Global School of Law Lisbon ( email )

Palma de Cima
Lisbon, 1649-023

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