I am playing as the Prince of Scotland and convinced my king to declare war on England. So far I have defeated roughly 20 of their lords, all of whom escaped. My strategy was to execute as many of them as possible so they couldn't really attack my castles. This worked against Ireland, Norway, and Gaelic Kingdoms but I cannot capture a single lord from England. Also, can I not capture kings? I have not been able to capture (and execute) a king.

Anyone know if there is a way to capture more often?