Ögedei had nominated his grandson Shiremun as his heir, but Güyük eventually succeeded him after the five-year regency of his widow Töregene Khatun. However, Batu, the Khan of the Golden Horde (also known as the Kipchak Khanate or the Ulus of Jochi) only nominally accepted Güyük, who died on the way to confront Batu. It was not until 1255, well into the reign of Möngke Khan, that Batu felt secure enough to again prepare to invade Europe. He died before his plans could be implemented.