Ferdinand I, king of Portugal (died 1383)

Ferdinand I, sometimes called the Handsome or occasionally the Inconstant, was the King of Portugal from 1367 until his death in 1383. He was also briefly made King of Galicia, in 1369. Facing a lack of legitimate male heirs, his death led to the 1383–85 crisis, also known as the Portuguese interregnum.

The Kingdom of Portugal was a monarchy in the western Iberian Peninsula and the predecessor of the modern Portuguese Republic. Existing to various extents between 1139 and 1910, it was also known as the Kingdom of Portugal and the Algarves after 1415, and as the United Kingdom of Portugal, Brazil and the Algarves between 1815 and 1822. The name is also often applied to the Portuguese Empire, the realm's overseas colonies.