Habeo with genitive

Question

Sīc scrīpsit Forcellīni:

K Græcorum littera est, non Latinorum, qui ejus loco c habent ejusdem potestatis.

What is the significance of the genitive case with habeō?

I gather that the sentence above means "K is a letter of the Greeks, not the Latins, who in its place give c the same meaning," i.e. habeō in its sense of "regard in a certain way". But I thought that that sense of habeō took a double accusative. Does the genitive here function like as in English "they regard c as producing the same sound"?

Can you show me a couple attestations of habeō, classical or otherwise, that illustrate its usage with the genitive in this way? Or if this meaning of the genitive also works with other verbs, an illustration or two of those?

Answer 1

Bearing in mind that letter names are generally indeclinable in Latin, I would parse this slightly differently:

K Græcorum littera est, non Latinorum, qui ejus loco [litteram] C habent ejusdem potestatis.
K is a letter of the Greeks, not of the Latins, who in its place have C, a letter of the same meaning.

In other words, I would take the ejusdem potestatis as an adjunct modifying [litteram] C, not another argument of habent.

Answer 2

This is called the genitive of indefinite value. In these situations the genitive is used when the verb is one of valuing or estimation. Examples of such verbs are: aestimo, duco, habeo and facio.