Imperial March

Needs Tours & Tournaments. Kaiser Heinrich IV (1066) can do it from the start: Activities, Grand Tour, Intimidation intent, and put every Powerful Vassal on the itinerary - then complete the tour without abandoning it. Fewer powerful vassals means a shorter route, so if your realm is sprawling, thin the list (or the vassals) first. Pairs mechanically with The Grandest Tour if you're touring anyway.