The Fifteenth Pius Dea Crusade, a religious war against the Baragwins, was initiated by the Pius Dea cult under the leadership of Supreme Chancellor Contispex XI. The Pius Dea-dominated Galactic Republic commenced an assault on Old Barag in 11,591 BBY. Neighboring worlds like Kinyen were also attacked during this religious campaign, citing religious freedom as justification. The Gran established the Tayan League, composed of former soldiers of the Doellin religion, to oppose Contispex's attempts to convert others to his faith.
The 2012 sourcebook The Essential Guide to Warfare marked the initial appearance of the Fifteenth Pius Dea Crusade. Although the text does not directly refer to the Fifteenth Crusade, it is depicted on a map illustrating the Crusades and their progression across the galaxy.