Learn Italian: Vi sono piaciuti i cimeli che ha consegnato il notaio? - Did you like the heirlooms that the notary handed over?

This is a prime example of subject-verb inversion in relative clauses. Placing the subject (il notaio) after the verb (ha consegnato) shifts the emphasis onto who performed the action, naturally highlighting that it was the notary, rather than someone else, who handed them over. This word order often sounds much more natural to an Italian ear than saying che il notaio ha consegnato.

Since "you" is the one doing the liking, why does the sentence use the plural verb sono piaciuti?

Remember that the verb piacere works backwards compared to the English verb "to like." The literal meaning of the Italian phrasing is "Were the heirlooms pleasing to you?". The grammatical subject of the main clause is actually the plural noun i cimeli (the heirlooms). Because the subject is plural, the verb takes the plural form sono piaciuti.

What role does Vi play at the beginning of the sentence?

Vi is the indirect object pronoun for the plural "you" (from voi). Because piacere structurally means "to be pleasing to," Vi sono piaciuti translates to "Were they pleasing to you all?" or "Did you (guys) like them?".

In the relative clause, why doesn't the past participle in ha consegnato agree with i cimeli?