Lion Rampant

From the White Wolf Wiki, the most complete White Wolf reference

Lion Rampant was a games company founded by Mark Rein•Hagen and Jonathan Tweet. Their most notable and influential project was Ars Magica, although they also developed other game products, notably Whimsy Cards.

Around 1990, Lion Rampant merged with White Wolf Magazine and formed the company that would eventually become White Wolf Game Studio (and later White Wolf Publishing, Inc).