Heyer essentially established the historical romance genre and its subgenre Regency romances. Her Regencies were inspired by Jane Austen, but unlike Austen, who wrote about and for the times in which she lived, Heyer was forced to include copious information about the period so that her readers would understand the setting. To ensure accuracy, Heyer collected reference works and kept detailed notes on all aspects of Regency life. While some critics thought the novels were too detailed, others considered the level of detail to be Heyer's greatest asset. Her meticulous nature was also evident in her historical novels; Heyer even recreated William the Conqueror's crossing into England for her novel "The Conqueror". In "The Great Roxhythe" Charles II is in need of some ready cash, and since Parliament refuses to bankroll his excesses, he turns to assorted foreign powers for financial aid.

The Great Roxhythe is Heyer's early masterpiece. It is an astonishing work of historical fiction, with two unconventional love stories at its center.