The first version of Sloanspace was based on ACES and was built by Caroline when she was working for Arsdigita. Sloan commissioned OpenForce to build dotLRN and port the existing Sloanspace content over to it.
As I posted on the wiki, I have an email from one of the managers who worked for Al at Sloan, dated 8/1/01, which starts out "I'm writing because OpenForce is ready to begin porting SloanSpace to ACS 4..." so I would put the birth date of dotLRN at very close to that date.