George Goodwin, who has written a book on Towton to coincide with the battle’s 550th anniversary in 2011, reckons as many as 75,000 men, perhaps 10% of the country’s fighting-age population, took the field that day.The archaeologists have done some impressive work on the site. They mention having learned something from the recent work at the Little Bighorn. If you're interested in reading about that research, this article is relevant, though I think it is not the same effort.
They had been dragged into conflict in various ways. Lacking a standing army, the royal claimants called on magnates and issued “commissions of array” to officers in the shires to raise men. Great lords on either side had followings known as “affinities”, comprising people on formal retainers as well as those under less rigid obligations. These soldiers would have been among the more experienced and better-equipped fighters that day (foreign mercenaries were there, too). Alongside them were people lower down the social pyramid, who may have been obliged to practise archery at the weekend as part of the village posse but were not as well trained. Among this confusion of soldiers and weaponry, almost certainly on the losing Lancastrian side, was Towton 25.
There was another English find recently covered by Smithosonian magazine, this one of a Viking mass grave in England. It is thought to be linked to the St. Brice's Day massacre of 1002, when Aethelred the Unraed proved he was ready enough.