Quote Originally Posted by Didz
Harold Godwinson, King of Wessex, London to Stamford Bridge, 3,000 men, 180 miles, 4 days.

They were probably mounted though, even though they fought on foot. I assume by 'on foot' you mean no used of horses wagons, railroads or boats by any of the troops for even part of the journey. Which actually writes off most rapid troops movements particualry as most armies included cavalry.
Well, it's ok if a part of te army has cavalry units, as long as they move at infantry speed. Railroads, boats, baloons, Mary Poppins' umbrellas are out.

As of Gengis Khan, can you provide numbers? How much distance, how many men, where, and who lead them?