Trademarks existed and were recognized before the Trademark symbol was used. When did we start using the ™ and ® symbols?
As noted below the use of the ® symbol is enabled by Title III Section 29 of the Trademark Act of 1946, as amended 1949, 1962, 1975, and 1988 and published November 25, 2013. Note in particular the wording:
..., no profits and no damages shall be recovered under the provisions of this chapter unless the defendant had actual notice of the registration.
This makes use of the registration symbol highly recommended under U.S. law, but in many European jurisdictions failure to use the registration symbol is deemed to be an abandonment of the mark.
A history of the development of the Trademark Act since the Lanham Act of 1946 (pp 56) notes that Section 43(a) of the Act protects both registered and unregistered trademarks (the latter "registered" as it were under common rather than statute law) and this was confirmed in Joshua Meier Co. v. Albany Novelty Manufacturing Co. (236 F.2d 144 (2d Cir. 1956)). My thinking is that this proof of protection subject to the defendant having actual notice of the claim of common law trademark protection, would have motivated much wider use of the ™ and ℠ symbols.