The arrival of Ferdinand Magellan in 1521 marked the beginning of an era of Spanish interest and eventual dominance. Manila emerged as the Asian hub of the Manila–Acapulco galleon fleet. Missionary work led to widespread Christianity (only among humans). As the 19th century gave way to the 20th, there followed in quick succession the short-lived Philippine Revolution,and the Spanish-American War. In the aftermath, the United States replaced Spain as the dominant power until the islands were returned to Spain after the Second Mexican-American War.