They appear on the map one by one during gameplay. They are spread out through Rome.
It's located in the Centro district of Rome.
The address of the Romulus Historical Society is: Po Box 74386, Romulus, MI 48174
The address of the Romulus Public Library is: 11121 Wayne Road, Romulus, 48174 0492
The Dark Brotherhood Sanctuary is located in the Cheydinhal East Gate.
There are no others you can acess other than the 1 in cheydinhal
The address of the Romulus Historical Society is: Po Box 177, Willard, NY 14588-0177
The Brotherhood Winery is located in Washingtonville, New York. It is the oldest winery in the United States founded by John Jacques and has been in operations since 1838.
The latest branch of Operation Brotherhood Montessori Center, Inc. is located in Fairview.
The Brotherhood Of Steel's Citadel is located on the western side of the Potomac River; north east of the Arlington Library
They are located all over the world.
If you mean Assassins Creed, Google it. There are plenty of maps.
They have a secret base, under Mournhold.