In an article about the development of the vaccine, it was mentioned that the first notice was by some French doctor who noted that nuns in a nearby convent never seemed to get cervical cancer, while the women in town did. So something about having sex (with men) created a risk of cervical cancer.
As for obscure STD’s - I never heard of chlamydia until I listened to Monty Python’s *Contractual Obligation Album * - “I’m dying from your love, my dear…” There was a full rundown of most known STD’s.