The Princess medical marijuana strain is a Jack Herer, found in a bought bag of cannabis in Amsterdam by Mr Soul from Brothers Grimm seeds.
Here is the story from Mr.Soul:
"I bought a 2 gram bag of Jack Herer buds (1996 Cannabis Cup winner) in Amsterdam at "Sensi Smile" coffee shop on Achterburgwal straat. The buds were supposed to be sinsemilla, but I was pleasantly surprised to find about a dozen seeds in the bud. I found the high to be cerebral and energetic, but not too long lasting; the buds appeared almost white due to resin coating. Of the 6 seeds I attempted to germinate, every one was successful and I got a 50% male and 50% female ratio."