When was 45 automatic pistol invented?

If by 45 automatic pistol you mean the 1911 Colt, then John Browning developed this design and the cartridge it uses between 1900 and 1904, producing his first prototype for testing in 1904. It was tested and modified, then adopted for service use by the United States in 1911, hence its designation as the M1911 Automatic Pistol. The design was further modified to create the M1911A1, which includes the grip safety.