The Abbey is the fifth mod made by Harry Mass Sr. It was released on August 8, 2000. It was the first in the Assault series. Set in the ruins of Monte Cassino abbey, the mod sends BJ Blazkowicz off on a mission to stop Dr. Schabbs before he's able to develop improved rocket fuel, giving Germany the capability to conduct strategic bombardment of the United States with their V-series weapons.
Similar to his SR series, this mod featured 5 levels played in Episode 1, here titled Assault, in a custom EXE based on registered Wolfenstein.
An SDL port was released on October 30, 2013.