Complex sentence: Juan de Hoyos and his family accompanied the later Ferdinand I, Holy Roman Emperor to Lower Austria in 1525, founding the Austro-Hungarian branch of the family, that rose to prominence in Austria and in Hungary as Hungarian magnates over the centuries.
Split into simpler sentences: Juan de Hoyos and his family accompanied the later Ferdinand I, Holy Roman Emperor, to Lower Austria in 1525, founding the Austro-Hungarian branch of the family. This branch rose to prominence in Austria and in Hungary as Hungarian magnates over the centuries.