The city grew slowly until the Civil War, when Houstonians voted overwhelmingly for the secession of Texas from the United States. During the war Houston was a lair for blockade runners, and on January 1, 1863, using two small vessels fortified with bales of cotton, it mounted a sea attack down Buffalo Bayou and helped recapture Galveston Island from Union forces that had seized the island three months earlier. In the same year Houston became the headquarters for the Confederate district of Texas, New Mexico, and Arizona. The period of Reconstruction lasted from June 20, 1865, when Houston was occupied by Union troops, until January, 1874. The city’s growth between then and World War I owed first to its importance as a railroad center and then to the Texas oil boom. Each of four wars, and even a fifth catastrophe, served Houston well. Its beginnings arose from the Texans’ victory at the Battle of San Jacinto. Though its people suffered to some extent from the Civil War and much more from Reconstruction, Houston got an economic stimulus from the presence of the Confederacy’s Trans-Mississippi headquarters. The city prospered during Reconstruction because many who abandoned the South moved to Texas. The greatest proportional growth of the city’s population, 111.4 per cent, came in the decade of the 1920s, largely a result of the impetus given by World War I. World War II led to the most successful period in Houston’s history. The city took a decisive lead in its long competition with Galveston after the Galveston flood and tidal wave of September 8, 1900, in which an estimated six thousand lives were lost and half the city was destroyed. The city’s most effective leaders in the first half of the twentieth century were Jesse H. Jones, a Secretary of Commerce and head of the Reconstruction Finance Corporation under President Franklin D. Roosevelt, and Oscar F. Holcombe, mayor of the city for eleven two-year terms between 1920 and 1957. Its most gifted, and anonymous, leader was Will C. Hogg, a son of James Stephen Hogg, the great governor of modern Texas. In 1926, at a personal cost of more than $50,000, Hogg organized the Forum of Civics with these words from Pericles as its motto: “No Athenian should ever confess that he neglected public services for the sake of his private fortune.” Hogg, an altruist and a man of wealth, died too soon to fulfill his dreams for the city. Four benefactors of indelible importance were William Marsh Rice, who endowed Rice University; George Henry Hermann, an eccentric who was born in Houston in 1843 and later gave the city a great hospital, Hermann Park, and Hermann Square downtown; and M. D. Anderson and Hugh Roy Cullen, the philanthropists.