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

Equatorial Guinea

Under the First Title, Fundamental Principles of the State, Article 2 of the Constitution of Equatorial Guinea grants the people with sovereignty to be exercised by way of universal suffrage (Constitute Project, “Equatorial Guinea's Constitution of 1991 with Amendments through 2012”).

Voting Rights and Suffrage · Country sources (all rights) · Years mentioned: 1991, 2012 · Last edited 2022-12-28 · Edit on GitHub