Alfonso XII of Spain was born on November 28, 1857, and became king in 1874 after a period of political instability in Spain. He was the son of Isabella II of Spain and was known for his efforts to restore the monarchy and stabilize the country following the turmoil of the First Spanish Republic. His reign lasted until his death on November 25, 1885, and is often remembered for promoting modernization and economic development in Spain. Alfonso XII's legacy includes the establishment of a constitutional monarchy and the strengthening of the Spanish military, which helped improve national unity.