This issue commemorates the official start of the settlement of the Azores, by a letter of 2 July 1439 in the name of King Afonso V:
To whom may see this letter we make known that Prince Henry, my uncle, told us that he had sheep set free on the seven islands of the Azores and, if it would please us, he would have them settled. And because it pleases us, we give him the place and licence to have them settled.”
Prince Henry the Navigator sends Gonçalo Velho, who had led the first Portuguese expeditions to the Azores in 1431 and 1432, to settle Santa Maria in 1439 and São Miguel in 1444, and makes him the donatary-captain of those islands. The full settlement of all nine islands would take several years, not least because the two western-most islands, Corvo and Flores, were only discovered in 1452. Besides Portuguese, settlers would include Jews escaping persecution on the continent, Flemish and other northern Europeans, and Arabs from northern Africa.
The stamps were designed by Carlos Alberto Santos, lithographed by the Mint on enamelled paper sheets of 5×10 stamps with perforation 12×12½ and two vertical phosphor bands, and circulated from 20 September 1989 to 31 August 1995.