Lair of Romulus

The Lairs of Romulus are secret locations featured in Assassin's Creed: Brotherhood that are similar to the Assassin's Tombs from Assassin's Creed II. Each lair of the Followers of Romulus houses a shrine to Romulus, which contains a variety of treasures. These lairs are scattered all over Rome and inclued platforming levels once found.

Each of the six lairs also contains a key, and a scroll, which each hold portions of a letter written by Marcus Junius Brutus. Obtaining all six keys allows one to obtain the Armor of Brutus, as well as the Dagger of Brutus, the two coveted treasures of the Followers.

On the map of Rome, each of the Lairs of Romulus are marked by a black wolf symbol. A seventh, gold version of the symbol marks the location of the aforementioned Romulus treasures.

These missions are side quests, as obtaining the Romulus treasures is not required to complete the main story of Brotherhood. The only the exception is the first lair encountered, the one within the Terme di Traiano, as it is a core memory, and is used to introduce the Followers of Romulus.

Terme di Traiano
This lair is the first one encountered, and its entrance is located at a low point of the terme, down a flight of stairs.

Palazzo Laterano
The entrance to the lair is located inside one of the gardens.

Terme di Diocleziano Ezio must completely repair the Aqueduct that leads into the terme to access the entrance to this lair, as it is situated high up in the wall of the initially empty terme. However, the entrance can also be accessed without repairing the Aqueduct by dropping over the ledge and climb-leaping into the archway.

Piramide Cestia
The entrance, though located next to the Pyramid, leads into the Catacombe di Roma.

Colosseo
The entrance is located at ground level between the inner and outer walls, just behind the stage of the Passion play.

Basilica di San Pietro
The entrance is outside, to the right of the staircase that leads to the inner sanctum.