What is the oldest written source in this country that mentions this right?
Antigua and Barbuda
In the constitution, Article 3, Section C protects the right to privacy in personal and family life, as well as the home.
References:
“Republic of Antigua and Barbuda / República Del Antigua y Barbuda Constitution of 1981 Constituciones De 1981.” Antigua and Barbuda: Constitution, 1981: https://pdba.georgetown.edu/Constitutions/Antigua/antigua-barbuda.html.