Premium banners are included starting from which expansion? Lords of the River?

And, more importantly, how many are included? Is it enough for a whole battle, or do I need the pricey premium banners pack anyway?

The banners included are enough for the new units of the expansion. If you want to replace the old banners of the core box set you have to buy the pack.

Lords of the River was the first expansion with the premium banners. 12 banners are included.

Thanks, I was afraid so.