This issue commemorates the death of Pedro Nunes in 1578, one of the greatest mathematicians and astronomers of his time. One of his best known contributions is the nonius, a measurement system to improve the accuracy of reading angles on the astrolabe for navigation, an important problem during the Portuguese period of Discoveries.
Aged 27, he was appointed Royal Cosmographer by King John III of Portugal. Nunes was also a professor of Mathematics at the University of Coimbra (1544-62). Nunes was an adept of the wide dissemination of knowledge, and as such wrote not only in Latin, the scholarly language of the time, but also in Portuguese and Spanish. A modern edition of his complete works is almost finished, as I write this.
The stamps were designed by the Post Office Art Department, lithographed by the Mint on enamelled paper sheets of 5×10 stamps with perforation 12×11½, and circulated from 9 August 1978 to 31 December 1983. The 5 Escudos stamp has a phosphor band.