This question concerns using the plural vos instead of the singular tu for polite address of a single person in Latin. This is not a classical feature but arises later.
When using this address, are the adjectives and participles referring to the addressee in singular or plural? My starting point is what we do in Finnish, transformed directly into Latin:
- Regular plural: Vos estis Romani/fati. (Te olette roomalaisia/puhuneet.)
- Polite singular: Vos estis Romanus/fatus. (Te olette roomalainen/puhunut.)
In Finnish there is a discrepancy in polite singular address: the pluralization only applies to personal forms of verbs, not to adjectives or participles. Does the same discrepancy appear in Latin?
I think it has to be there for nouns. It makes little sense to say vos estis reges to say politely "you are a king", so I would expect vos estis rex. But with participles and adjectives I feel it could go either way. Which way does it go? Are there perhaps examples of both?