Original: In England a Catholic male heir to the throne , James Francis Edward Stuart , had been born , and the letter asked William to force the ruling king , his father-in-law James II of England , by military intervention to make William 's Protestant wife Mary , James 's eldest daughter , heir , preferably by establishing that the newborn Prince of Wales was a fraud .
Simplified: In England a Catholic male heir to the throne , James Francis Edward Stuart , had been born . The letter asked William to force the ruling king , his father-in-law James II of England to make William 's Protestant wife Mary , James 's oldest daughter , the heir .