Did you know that string theory began in Pisa? So said Gabriele Veneziano in the first talk of his special course on string theory here in Pisa, entitled "The Birth of String Theory: A Personal Recollection". Perhaps he was indulging the audience. Perhaps. He told us that as a graduate student from the University of Florence he came in the Spring of 1966 to listen Sergio Fubini's talks in Pisa and really this was the beginning of the path towards a theory of strings. Of course, at that time string theory was not being proposed as a theory containing gravity but rather as a theory of the strong interactions. Veneziano described working on current algebras and superconvergence relations at the Weizmann Institute in 1966-67 and listening to Murray Gell-Mann's talk at Erice in July 1967 as being important in leading him to a dual resonance model.
From Gell-Mann, he learned about Geooffrey Chew's "expensive" bootstrap method for calculating scattering amplitudes. Chew' s bootstrap he said related objects of different types; baryons in the s-channel became mesons in the t-channel. And the rest of the story as they say is history.