The Ram is an infantry unit that is usually used to counter enemy buildings. It is slow compared to other artillery, but effective against buildings. It is not considered true artillery, and is therefore not vulnerable to Culverins, however it can be easily killed by any unit with multipliers against infantry (such as most artillery, Lancers, and Jat Lancers). It has a high siege attack which makes it turn enemy bases to dust in mere minutes. Four or five can do considerable damage to an enemy base.
But despite of this high siege damage the Ram has no melee or ranged attack, making it very vulnerable against enemy attacks. Without any support the Ram cannot stand long in a protected enemy base. If the player is actually trying to wreck the enemy's hometown without any support units, do it in discreet. One could sneak 20 of these, 5 at a time through the edges of the map without being seen. Then, draw the attention of the enemy with Forest Prowlers and use the Rams to destroy enemy's important buildings such as military buildings, factories, and even town centers. Then simply put the Forest Prowlers back to stealth mode and watch how the Rams demolish buildings.
The Ram is capable of targeting ships along the coast and are devastating against Galleons (as they often are training units along the shoreline). They are the only land hard counter to ships until Light Cannons are available in the Industrial Age.
Rams, much like Mantlets, are upgraded by both Infantry Combat cards and Siege unit upgrade cards.
Along with the Flail Elephant, the Ram is the only melee siege weapon in Age of Empires III and they are also the only two units with a siege RoF of 1.5.
The most direct way to attack a stone wall or other stone fortification was to knock it down with a battering ram. A typical ram was a stout log mounted on wheels or suspended from a frame so it could swing forward and backward. The frame was brought up to the wall or gate to be battered; men heaving in unison then repeatedly slammed the ram into the target. Given enough time, any obstruction could be knocked down, opening a breach for assault.