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

Haiti

Under Article 17, Haitians 21 years or older may participate in universal voting regardless of sex or marital status. (Constitute Project, “Haitian Constitution of 1987 with Amendments through 2012”).

Voting Rights and Suffrage · Country sources (all rights) · Years mentioned: 1987, 2012 · Last edited 2022-12-28 · Edit on GitHub