How recently is "relatively recently"? When did the nation's collective consciousness start losing its grip on this important and fundamental truth?
It is good that you keep bringing this to the forefront. The nation's memory needs to be jarred awake.
Birthers have had trouble finding evidence this was a widespread belief at any time in our history. It certainly wasn't widely known in 1856 when the Republican party's candidate, John C. Fremont, ran for President with no objections, despite having a French father.
Or in 1854, when then Secretary of State W.L. Marcy responded to someone concerned about the citizenship of aliens by telling him, "...every person born in the United States must be considered a citizen, notwithstanding one or both of his parents may have been alien at the time of his birth. This is in conformity with the English Common Law, which law is generally acknowledged in this country, and a person born of alien parents would, it is presumed, be considered such natural-born citizen, in the language of the Constitution, as to make him eligible for the Presidency."