Tammany Hall is a game of backstabbing, corruption, temporary alliances and taking power at all costs. If you want to rule New York, you are going to need to play the cities growing immigrant populations against one another. Help the immigrant groups who owe you political favors, call in those favors to slander your rivals and win election.
Tammany Hall was the political machine that dominated New York City politics by organizing the immigrant populations. While the organization's influence spanned from its founding in the 1790's to its collapse in the 1960's this game is set in lower Manhattan roughly between 1850 and 1870; the era of Boss Tweed.