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

Mexico

Mexico has had several constitutions throughout its history with the first, the Constitution of Apatzingán, being in 1814. In Chapter V, Article 40 of the Constitution of Apatzingán, citizens are guaranteed the right to express themselves and manifest their opinions.

Sources:

Freedom of Expression · Country sources (all rights) · Last edited 2024-08-12 · Edit on GitHub