João I of Portugal was the King of Portugal from 1385 until his death in 1433. He was a member of the Aviz dynasty and came to power after the decisive Battle of Aljubarrota, which secured Portugal's independence from Castile. His reign marked the beginning of a period of stability and growth for the nation. Under João I, Portugal began to expand its overseas exploration, laying the groundwork for the Age of Discoveries. He established strong alliances, including a notable marriage to Philippa of Lancaster, which strengthened ties with England. His leadership helped shape Portugal's future as a maritime power.