When did rec's become a thing?

[naraht]

OK, to be more clear, I completely agree that recs have been private for a while, but for Always?

Does the concept of expecting that rushees for the NPC sororities have recs go back to the founding of the NPC in 1902? And if not, did it start pre World War II?

For that matter, when did the members of the NPC go to the concept of girls pretty much rush all of the sororities as a group (as opposed to the NIC and NPHC which aren't anywhere near that concept)