Can't find too much today!
September 14, 1435 - John, Duke of Bedford, younger brother of Henry V and at one point Regent of England for his nephew Henry VI, died in Normandy.
September 14, 1752 - The 3rd of September became the 14th when the Gregorian Calendar was introduced into Britain.
September 14, 1851 - American author, James Fenimore Cooper, died. He is best known for his Leatherstocking Tales featuring Natty Bumppo (Last of the Mohicans).
September 14, 1852 - The Duke of Wellington, victor of Waterloo, died at age 83.