After showing modest form as a juvenile in France she emerged as a top-class performer in the first half of 1957 when she was an unlucky second in the Princess Elizabeth Stakes before winning the 1000 Guineas and finishing third in the Epsom Oaks.
[3] She was sired by Prince Bio, who won the Poule d'Essai des Poulains in 1944 and became a very successful breeding stallion whose other offspring included Sicambre.
On her three-year-old debut Rose Royale was sent to England to contest the Princess Elizabeth Stakes over eight and a half furlongs at Epsom Racecourse and looked a most unlucky loser as she finished second to the Queen's filly Carrozza.
[3] The French jockey Jean Massard took over from Smirke when Rose Royale was stepped up in distance and started 11/10 favourite for the Oaks Stakes at Epsom on 7 June.
[5] Later in October she was back at Newmarket for the ten furlong Champion Stakes and started at odds of 5/2[6] against opponents including Ballymoss and the Coronation Cup winner Fric.