Alexander Dyce, A General Glossary to Shakespeare's Works

Acheron A MIDSUMMER-NIGHT'S DREAM, iii. 2. 357 ; TITUS ANDRONICUS, iv. 3. 44 ; MACBETH, iii. 5. 15.It is not a little amusing to find Malone almost persuaded by a Mr. Plumptre that, in the last of the passages just referred to, the poet was thinking of“Ekron” in Scripture. Did these matterof-fact commentators suppose that Shakespeare himself, had they been able to call him up from the dead, could have told them“all about it?” Not he;—no more than Fairfax, who, in his translation of the Gerusalemme (published before Macbeth was produced), has made Ismeno frequent “the shores of Acheron,” without any warrant from Tasso: “A Christian once, Macon he now adores,
Nor could he quite his wonted faith forsake,
But in his wicked arts both oft implores
Helpe from the Lord and aide from Pluto blake;
He, from deepe caues by Acherons darke shores
(Where circles vaine and spels he vs'd to make),
T' aduise his king in these extremes is come;
Achitophell so counsell'd Absalome.” B. ii. st. 2. The original has merely “Ed or dalle spelonche, ove lontano
Dal volgo esercitar suol l' arti ignote,
Vien,” etc. For instances how loosely the name Acheron is used by our early poets, see, in Sylvester's Du Bartas, ed. 1641, The Second Day of the First Week, p. 15, The Vocation, pp. 149, 155, and The Fathers,p. 162 ; also Hubert's Edward the Second, p. 161, ed. 1629.