Why was the existential quantifier symbol ∃ based off of an inverted "E"?

Question

Peano introduced a number of logical symbols still used today:

• ∨ (from Latin vel)
• ∧ (inverted ∨)
• ∃

This inversion of Latin letters as symbols (and inversion of symbols to signify their 'opposite' operation) was followed by later logicians:

• ∀ (Gentzen, 1935: inverted A from "All-Zeichen", by analogy to ∃)
• ⊥ (inverted ⊤)

I had always assumed that ∃ stood for "E" in "Existential" / "there Exists", but Peano wrote and introduced this symbol in French, not using any words beginning 'E':

Mais nous préférons l'indiquer par la nouvelle notation

Ǝa

qu'on peut lire « il y a des a ».

• Formulaire de mathématiques, Peano (1897)

So why did he choose an inverted "E"?

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^{Earliest Uses of Symbols of Set Theory and Logic
What came first, the $\forall$ or the $\exists$?}