Wildfire (1986)- Followmy.tv

In this animated Hanna/Barbera series, the kingdom of Dar-Shan is placed under a curse by the evil Diabolyn, Queen Serena is desposed and her daughter Sarah and her husband Prince Cavan are exiled to Earth. Prince Cavan is stripped of his memories and believes he is John Cavanaugh, a rancher in the American Southwest. Sarah is unaware of her heritage until the day that Wildfire, an intelligent magical horse and the Royal Family's Champion, travels to Earth to bring Sarah to Dar-Shan and aid in whatever problem sthey have. Each week Sarah travels to Dar-Shan with Wildfire, typically to thwart the schemes of Diabolyn as she tries to take the throne and become Queen.