AdvertisementAdvertisement AdvertisementSophie Fouracre was competing at Swalcliffe Park Equestrian in Oxfordshire in the United Kingdom on Saturday, July 18, when she fell from her horse, Rhubarbsfox Britannia. Sophie Fouracre with her kids via FacebookCredit: Sophie Fouracre/FacebookHer cause of death was confirmed as "massive trauma" following a post-mortem, per court documents reviewed by PEOPLE on Tuesday, Aug. 11. AdvertisementAdvertisement AdvertisementShe also picked up a horse sired by Speedway, which is owned by King Charles, calling it "such an honor." AdvertisementAdvertisement AdvertisementRosie Williams, chief executive of British Eventing, said in the statement that the "British Eventing community is heartbroken." Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!