User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-10750309-20130718140216/@comment-3146930-20130718234445

The best example is that part in The Mark of Athena when Hazel, Frank, and Leo are looking for Nico. Leo finds that lock and says it has to a Greek design because it isn't complicated enough to be Roman. Even if Leo isn't exactly being mean, both Frank and Hazel get mad at him. Most likely because Frank mentions in The Son of Neptune that the Romans took the Greek concept of the gods and improved them. The Romans believe they made them better, even if the Greeks seem to be better at certain things over the Romans.