User blog comment:Darkcloud1111/The Rules of Death and The Son of Neptune/@comment-4388405-20110907024652/@comment-4142691-20110907155919

I think the feast they are referring to is Fors Fortuna which is on june 24th. People migrated towards her temple(s), they proceeded along the Tiber, both on the banks of the river and in the river itself. June 11th is Tyche's sacred day, but her festival itself was on the 24th of the same month.