AUC 1:3:7

[cinefactus]

mānsit Siluiīs posteā omnibus cognōmen, quī Albae rēgnārunt.
I can't figure out why it is not Silvii or Silvius. What am I missing?

 

[AoM]

From Gould and Whiteley’s commentary:

“Silviis, should logically be in agreement with cognomen, ‘the clan name Silvius’, but is attracted into the case of omnibus.”

 

[cinefactus]

Thanks, that was what I was wondering, but it just seemed a bit odd.

 

[Pacifica]

It's a common case of attraction. It also routinely happens with the mihi nomen est construction (to which Livy's is obviously similar). More generally, it tends to happen wherever some word that should logically be in another case describes someone who's also represented by a dative word. For example, nobis beatos esse licet is the logical construction (and it can occur) but nobis beatis esse licet is usual.