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.”