Name me please some interesting episodes involving mercenaries?

I mean guys with weapons that fought for money.For instance,I heard of the episode,where they were payed by a Henry VII of England's enemy,who attemted to overthrow Him to get the kingdom for himself.He payed some german mercenaries,collected in Holland, who,after joining his invading England army,greatly increased his chances to become the king of England himself.Where can I read such stuff online?