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

Honduras

According to Article 5, voting is seen as a public duty. All Honduras citizens, by definition over the age of 18, are obligated to vote in universal, egalitarian, direct, free, and secret elections. (Constitute Project, “Honduras’ Constitution of 1982 with Amendments through 2013”).

Voting Rights and Suffrage · Country sources (all rights) · Years mentioned: 1982, 2013 · Last edited 2022-12-28 · Edit on GitHub