CoreStates Financial Corporation, previously known as Philadelphia National Bank (PNB), was an American bank holding company in the Philadelphia, Pennsylvania, metropolitan area. The bank was renamed in the mid-1980s after a series of mergers. After being acquired by First Union Corporation, which later also acquired Wachovia National Bank to become Wachovia Corporation, CoreStates Financial Corporation became a part of Wells Fargo in 2008 when Wachovia (formerly known as First Union) was acquired by that company.