And I disagree with one point, Longswords, along with Goths, are also viable as a front line in Castle with Vikings (+15 HP) and Japanese (+15% ROF) since they are cheap and easy to mass. During Feudal/Castle transition, when I can I like to pump Infantry from three barracks at a time, when I hit Castle I got 25 infantry ready for battle. If used smartly, and mixed with one or two mangonels they can be devastating in Castle Age.