Cataphracts will absolutely butcher massed Longbows.

There is nothing the English can do in feudal age against Varangian Guards. However, a large clump of Longbows can grind down Varangians if you only have one or two, so thin out the Longbows first.

While the English player steals deer, the Byzantine can prioritize berries for the extra olive oil, moving onto a second berry bush and ignoring the deer.

If you are playing English, when getting a group of longbowmen out there, bring a Spearman with it, because Horsemen can really pick off those reinforcements rather quickly. Having longbowmen just out in harm's way could prove devastating.