The Morgan Dollar was the first standard Silver Dollar struck in the United States Mint since early 1873. This series derives its name from its designer, George T. Morgan, who was formerly a pupil of the famed William Wyon in the Royal Mint in London. Authorized by the Bland-Allison Act of February 28, 1878, the Morgan Dollar was produced every year from 1878 through 1904. The coin was essentially an outlet for western mine owners who were having difficulty selling silver bullion on the world market. The use of the Morgan Dollar for this purpose received a further boost with the Sherman Silver Purchase Act of July 14, 1890, but it was finally halted in 1904 when the bullion supply became exhausted. Since the 1918 Pittman Act called for the replacement of all the Silver Dollars that the government melted at the end of World War I, and the new Peace design was not yet ready for production, the Morgan design was revived for one final mass coinage. The original hubs had been destroyed, however, as the Mint did not expect to strike any more coins of this denomination after 1904. As a result, it had to create new hubs for the Morgan Dollar in 1921, and examples of this date are slightly (yet perceptibly) different in design from earlier coins of this type.