Thank you for your message. I am from Arecibo. Is in this town of PR that you find most of the Classen's family name. My grandfather Demetrio Classen died several year ago and I do not know much about his parents. I know this is not an usual last name as is Class or Clas. As a matter of fact, when I give my last name, many people as suprised and in occassions have asked I spell it. I am sure the same is with you. There are a few Classen in some other towns of PR but as far as I know they originated in Arecibo. If you find any new info. please let me know, I will do the same for you. Take care.