Comment by CalChris

Pseudonymity was a common practice at the time. Also, the Federalist Papers were written before the First Amendment. Indeed freedom of the press was proposed in No. 84.

http://alturasinstitute.com/wp-content/uploads/2016/08/Salad...

The Articles of Confederation mention Freedom of speech and debate in Congress but that's it. Otherwise, this was left to the States.