Queen Elizabeth II will turn 90 on April 21st and royal party planners extended the invitation to jockeys of the Palio in November.
Planners hoped they would come and parade for the Queen, who is renowned for her love of all things equestrian.
The jockeys of the 17 contrade – the wards of the city who compete in each race – were reportedly eager to accept the invite but eventually, organizers declined the invitation over logistical concerns.
“It was mostly for organizational issues, as well as ethical ones,” Siena Mayor Bruno Valentini told La Stampa.
Italian media sources report that Palio officials were concerned that it would not be possible to erect a temporary structure large enough to do justice to the Palio's history.
The race, which started in its modern form in 1656, is held twice a year on July 2nd and August 16th, and only lasts about 90 seconds. Riding bareback, the jockeys circle the Piazza del Campo three times.
“The theatre of the Palio is the piazza,” explained a spokesperson for the Magistrate of the Contrade, the group that oversees the Palio's organization. “Outside of that space it doesn't make any sense.”
Although it is not feasible to send the Palio's horses to England, Valentini said the Queen was always welcome to come and watch the event live in Siena.
“If she would like to see the Palio she needs to come here. Perhaps she can even visit our museum dedicated to the contrade,” the mayor said.
“We would formally like to invite her to Siena, where she can watch the event directly from the window of our town hall.”
The city is no stranger to visitors from the court of England, with the Queen's late sister, Princess Margaret, once being a royal guest during the Palio.