Which social factor allowed tammany hall to become an urban power in the 19th century?

Tammany Hall, also known as the Society of St. Tammany, the Sons of St. Tammany, or the Columbian Order, was a New York City political organization founded in 1786 and incorporated on May 12, 1789, as the Tammany Society. It was the Democratic Party political machine that played a major role in controlling New York City and New York State politics and helping immigrants, most notably the Irish, rise up in American politics from the 1790s to the 1960s. It typically controlled Democratic Party nominations and political patronage in Manhattan from the mayoral victory of Fernando Wood in 1854 and used its patronage resources to build a loyal, well-rewarded core of district and precinct leaders; after 1850 the great majority were Irish Catholics.