This is quite a mistake about Mac Flecknoe. This poem was published in 1682, and was the result of the attacks made on Dryden by Shadwell in the 'Medal of John Bayes'; cf. note. Mac Flecknoe by its name alluded to Richard Flecknoe, then dead four years. He had been author of many works, and him Dryden declares to have been
'Through all the realms of nonsense absolute';
and he goes on to say how when Flecknoe died he left Shadwell his successor
'With double portion of his father's art' (—Dunciad. Cf. Life of Pope, p. 169 sq.)