Ruling on things that were done at the time of the Prophet (peace and blessings of Allaah be upon him) which he did not know about

Perhaps minor issues which happened but he did not know about them are not included in that. But with regard to things which were widespread and well known, the basic principle is the hadeeth of Jaabir: “We used to practice coitus interruptus (‘azl) at the time when the Qur’aan was being revealed.”