One of the people on my "friends" list, thus proving once more how silly it is to call it that, is Samuel Pepys, pepysdiary.

Yesterdays entry, for Saturday 19 April 1662:

This morning, before we sat, I went to Aldgate; and at the corner shop, a draper’s, I stood, and did see Barkestead, Okey, and Corbet, drawn towards the gallows at Tiburne; and there they were hanged and quartered. They all looked very cheerful; but I hear they all die defending what they did to the King to be just; which is very strange. So to the office and then home to dinner, [..]

There are links to the various names. Turns out that what they "did to the King" was be signatories to Charles I's death warrant and, with the restoration of the monarchy, that was enough to get one yourself.

Their final speeches and prayers are here, which brought home again what a resource the internet is.

I'm also quite impressed that they had chances to avoid their fate, having been abroad, but returned.