where is the sixth lair? You need to completely repair the aqueduct that leads into that area before you can access the lair, though. When you do, the water level will rise and you'll be able to reach the entrance from the surface of the water. I've beaten the main story, renovated all buildings and I've completed five of the lairs of Romulus (Palazzo Laterano, Terme Di Diocleziano, Piramide Cestia, Terme Di Traiano, and Colosseo.) Hi, was wondering if anyone can help? How do I reach the Treasure Chest in Campagna District - near Terme Di Diocleziano? where is the last lair of Romulus? For Assassin's Creed: Brotherhood on the Xbox 360, a GameFAQs message board topic titled "Lair of Romulus in Terme di Diocleziano? I did not get the treasure chest in Campagna Dist...at Terme Di Diocleziano, and the chest is outside the Romulus Lair BEFORE I repaired the aqueducts, and the pit is now flooded with water. For Assassin's Creed: Brotherhood on the Xbox 360, a GameFAQs message board topic titled "How do you get to the Romulus lair in Terme di Diocleziano? The lair's entrance is in a cave up in the wall, just beneath the ground. ". ".