In Eric's Dining hall, a portrait can be seen above the fireplace depicting a couple that looks suspiciously like Aurora and Phillip from Sleeping Beauty. Considering how large the painting is for an area that is for public dining, it's obvious that they have some importance to Eric's lineage. This may suggest they are Eric's ancestors, meaning Sleeping Beauty and The Little Mermaid take place centuries from each other.

http://disney.wikia.com/wiki/Prince_Eric's_Castle
И действительно!