Bouyant market, international expansion and market diversification kept Saint-Gobain on an upward trend for three-quarters of the century. The glass industry blossomed during the second half of the 19th century. Worldwide production grew practically 9% a year from 1850 to 1870 , and Saint-Gobian start honing its strategy to stay on the move and thereby fend off foreign competition. It merged with its main domestic rival, Saint-Quirin, in1858.