In the past, UNIDROIT'S main efforts in the field of unification consisted in seeking to unify existing rules of domestic law where these rules concerned activities which had a sufficiently transnational dimension to make the absence of international rules a major source of legal uncertainty for commercial parties. This was, for instance, the case with UNIDROIT'S preparation of the two 1964 Conventions on the international sale of goods and its preparation of the 1983 Convention on agency in the international sale of goods.