What is the oldest written source in this country that mentions this right?

Kiribati

Under Article 64, every citizen of Kiribati who is over 18 and is a resident of one of the electoral districts established by the Kiribati constitution is entitled to be an elector in the district in which he is a resident. The person may then vote for his representative in the Maneaba ni Maungatabu. (Constitute Project, “Kiribati’s Constitution of 1979 with Amendments through 2013”).

Voting Rights and Suffrage · Country sources (all rights) · Years mentioned: 1979, 2013 · Last edited 2022-12-28 · Edit on GitHub