Even in 1500 their cavelry is superior to yours and they are using quite a lot of it. You need to being in larger armies using a little more cavalry (but not more than 50% cavalry. If a western power uses more than 50% cavalry they'll lose a bonus that reduces losses in battle).
You're England, you should be able to bring in more men than that.
You're England, you should be able to bring in more men than that.