Princess Anne, the younger sister of King Charles, has been hospitalized after sustaining minor injuries and a concussion in an “incident” at her home, according to Buckingham Palace.

The Palace released a statement earlier today confirming that Anne, 73, was hospitalized as a precaution after suffering the injuries, though the exact cause remains unconfirmed.

According to CNN, a source alleged that the princess was walking close to horses on her estate in Gatcombe Park, Gloucestershire, western England, when the incident occured.

Again, the exact cause behind the injuries hasn’t been made public yet, though Princess Anne’s medical team have said that her injuries are consistent with a potential impact from a horse’s head or legs.

“The Princess Royal has sustained minor injuries and concussion following an incident on the Gatcombe Park estate yesterday evening,” the statement from Buckingham Palace said Monday.

“Her Royal Highness remains in Southmead Hospital, Bristol, as a precautionary measure for observation and is expected to make a full and swift recovery.”