Duarte I's reign lasted just five years before his death from plague in 1438, making all issues from this period inherently short-lived. The "Preto" designation — from the Portuguese for black — reflects the heavily debased copper alloy used for these low-denomination pieces, which darkened aggressively in circulation. Porto's mint was one of several active under Duarte, though output was modest given the reign's brevity and the crown's financial pressures inherited from João I's costly North African campaigns at Ceuta.
Duarte I's reign lasted just five years before his death from plague in 1438, making all issues from this period inherently short-lived. The "Preto" designation — from the Portuguese for black — reflects the heavily debased copper alloy used for these low-denomination pieces, which darkened aggressively in circulation. Porto's mint was one of several active under Duarte, though output was modest given the reign's brevity and the crown's financial pressures inherited from João I's costly North African campaigns at Ceuta.