The first assertion of the right of association in Iceland is in their 1944 Constitution, ratified on June 17, 1944. The right was asserted in Chapter VII, Article 74 (“Constitution of the Republic of Iceland”, 1944).

1944. Constitution of the Republic of Iceland. June 17. https://www.government.is/library/01-Ministries/Prime-Ministrers-Office/constitution_of_iceland.pdf.