What happens if I file multiple foreign applications for the same invention?

When multiple foreign applications are filed for the same invention, the right of priority is generally based on the earliest filed application. MPEP 213.03 explains: ‘The twelve months is from earliest foreign filing except as provided in 35 U.S.C. 119(c). If an inventor has filed an application in France on October 4, 1981, and an identical application in the United Kingdom on March 3, 1982, and then files in the United States on February 2, 1983, the inventor is not entitled to the right of priority at all; the inventor would not be entitled to the benefit of the date of the French application since this application was filed more than twelve months before the U.S. application, and the inventor would not be entitled to the benefit of the date of the United Kingdom application since this application is not the first one filed.’

However, if the later application contains additional subject matter, a claim specifically limited to that additional disclosure may be entitled to the priority date of the later foreign application.