Smith/Ragan article & chapter 1

Sort of a chicken or egg dilemma: Did Robert Gagne first inform instructional design theory or did theory provide a foundation for Gagne's work?

On page 4 in chapter 1, the authors acknowledge that the Dick and Carey Systems Approach model has been "heavily influenced by the work of Robert Gagne." And the Smith/Ragan definition of instructional design seems to resonate with Gagne's 9 instructional events. "The term instructional design refers to the systematic and reflective process of translating principles of learning and instruction into plans for instructional materials, activities, information resources, and evaluation" (Smith/Ragan, 1993, p. 2). Contrast this to the 9 events: 1] gaining attention; 2] informing learners of the objective(s); 3] stimulating recall of prior learning; 4] presenting the content; 5] providing the learning guidance; 6] eliciting performance; 7] providing feedback; 8] assessing performance; and 9] enhancing retention and transfer (Driscoll, 2005, p. 373).

I detect certain parallels, and while a connection between Gagne and instructional design theory seems quite evident, I wonder which emerged first?