An attack (oppugnatio) upon a fortified place, such as a walled town, and     
 a siege (obsido) involved the following devices and tactics:

     1. agger (same term used in the construction of a camp), a sloping plane made     
 of earth, stones, and logs, begun at a distance from the enemy's wall, and    
  gradually lengthened and raised untill the top was on a level with the top      
of the wall. Tha agger was used as a menas of approach and for moving up siege    
  machines.

 2. aries, a battering ram made of heavy log with a metal head, used for battering   
   down the enemy's wall or making a breach in it. The aries (literally ram)    
  derived its name from the metal head that was usually in the form of a ram's      
head.

 3. pluteus, a small, movable, wooden screen, used as a protection for a group     
 of soldiers advancing or under attack.
   
  4. scala, a ladder for scaling walls.

     5. testudob, a protective screen formed my the overlapping of shields held      
above the heads os soldiers as the moved foward in close formation. Teh term     
 was also applied to a wooden shed with a slanting roof, used to cover solidersnear      
the enemy wall. The testudo (literally tortoise) derived its name from its      
resemblance to the shell of a tortoise. 
     
6. turris ambulatoria, a huge, movable, wooden tower, several stories high,     
 with a platform for the besiegers to reach the top of the enemy wall. the      
turris, the height of which varied from 50 to 180 feet high, was moved fowardon     
 rollers. 
     
7. vinea, a heavy, movable shed, mounted on rollers. Several were ofetn placed     
 together along the agger to protect the men fighting close to the walls of      
the enemy. The vinea (literally vineyard) derived its name from its resemblance    
  to a grape arbor.

     In storming a town the Romans made use of tormenta (artillery), of which there      
were three common types:

     1. ballista, a machine for hurling heavy stones and blocks of wood.

     2. catapulta (catapult) for hurling stones and darts.

     3. scorpio, a high catapult for hurling stones and darts