A Name Known Throughout the World

Legendary splendour is the top of the dynasty ladder, and almost any long campaign gets there eventually - renown flows from living dynasty members, especially landed ones and those married into power. If you want it fast, the Yamato dynasty in Japan starts at Fabled (one level short) in every start date, with landed members to play from 867. Otherwise just let it accumulate alongside A Legacy to Last the Ages and Prolific - the same dynasty-growth engine drives all three.