The Pegasus conundrum:

 

Reid appears to be correct, when she states that "In a post-classical interpolation Perseus is often seen riding the winged horse Pegasus rather than flying through the air on his winged sandals." (Reid, OGCMA, s.v. “Perseus and Andromeda,” 875)  And, further: “In painting from the Renaissance onward, Pegasus is shown bearing Perseus to rescue Andromeda.” (Reid, OGCMA, s.v. “Pegasus,” 847)

 

Classical authors seem to keep it straight:

       Bellerophon rides Pegasus.

       Perseus gets about via the talaria Hermes loans him.

 

Perhaps the medieval tradition is to blame for the confusion that puts Perseus on Pegasus. (Cf. D. Javitch, “Rescuing Ovid from the Allegorizers,” Comparative Literature 30 (1978): 97 – 107)

In Renaissance (e.g. 1554), Titian’s purist reformation of the mythological iconography seemed to be in order.

 

HOWEVER, classical astronomers as early as 230 BC were already putting a horse into the constellations that catasterize the story of Andromeda's rescue. Sometimes the horse is winged (cf. Arat. Phaen. 205-224)  sometimes not. But, the horse is there. Is it right to call it Pegasus?  (See the Flamsteed skychart.)

 

Ovid, in Met. 6 passim, seems preoccupied with getting Perseus here and there on his winged sandals.

Perhaps the tradition of putting the hero on Bellerophon's horse had already begun?

 

Indeed, N. Yalouris's account of the Pegasus myth would suggest that the line between Bellerophon and Perseus, as rider of Pegasus, was not nearly so clean-cut in antiquity, either!

            N. Yalouris, Pegasus: ein Mythos in der Kunst (Mainz 1987).