That should be at the time of the founding of our nation, not the founding of our Constitution. The Articles of Confederation have been replaced by the Constitution which gives the authority to Congress to establish uniform rules of citizenship.
Lucy, I wrote what I meant ... at the founding of our Constitution. This is the instrument that gave naturalization powers to Congress. States still had the power to define citizenship in their states. It's not until the 14th amendment that citizenship powers became consolidated at the federal level.