User blog comment:Zathronas/Speculative author: Who is Summer Rose?/@comment-5217560-20140809062848/@comment-96.254.157.84-20140810141215

That's not much to go on. Given how old Ozpin is, he could have any number of friends over the course of his lifetime. He's also friends with Ironwood, Qrow, Dorthy, the Cowardly Lion, Cinder was hinted to be his student, and he most likely knew Summer and Schnee.