Congregation Mikveh Israel (officially Kahal Kadosh Mikveh Israel), is also known as the "Synagogue of the American Revolution". The oldest Congregation in Philadelphia, Mikveh Israel was informally established by religious minded Jews in British America during the 1740s, and has become the second-oldest surviving Congregation in the United States. In Pennsylvania, and Philadelphia in particular, Jews found an environment of tolerance for their religious beliefs and traditions made possible by William Penn's 'great experiment'. By 1775 a community 300 strong existed in a city of 35,000. Among items in the archives of Congregation Mikveh Israel are letters written by George Washington and Abraham Lincoln, and a public subscription list for the 1782 building signed by Benjamin Franklin, David Rittenhouse, and other civic leaders.