They belong with Tanks and fighter jets?
I arrange my units the same way they are in the game.
Modern is post-WW2.
http://forums.civfanatics.com/downloads.php?do=cat&id=23
Industrial = 1700 AD - 1900 AD
Modern = 1900 AD +
From this, you could put your Polish cavalry in Modern instead of Industrial.
You decided otherwise. Fine for you. But perhaps others don't want to follow your standard.

And it would make a lot of sense, too (it's easier to find certain equipment when the WW1 and WW2 stuff doesn't get mixed with the modern stuff).
Great News!

