Complex sentence: She was one of only four Princesses of Wales who never became queen consort as her eldest son succeeded her father-in-law as George III of the United Kingdom in 1760 rather than her her spouse, who had died nine years earlier.
Split into simpler sentences: She was one of only four Princesses of Wales who never became queen consort. Princess Augusta's eldest son succeeded as George III of the United Kingdom in 1760, as her husband, Frederick, Prince of Wales, had died nine years earlier.