Frateris Templar
The Frateris Templar were the military order of the Ecclesiarchy for several centuries.
Founding
The Frateris Templar were founded soon after the Ecclesiarchy moved away from Terra and to the planet Ophelia VII in order to escape Administratum control. The Frateris Templar was an all male military order and operated effectively as the private army of the Ecclesiarchy.
The Age of Apostasy
Three hundred years after their founding the Ecclesiarchy moved back to Terra and the insane Goge Vandire seized the Ecclesiarchy as his own. When a man known as Sebastian Thor organised a confederation to resist Vandire's tyranny, he sent the Frateris Templar to destroy him. However en-route to the planet the Templar fleet was engulfed in a warp storm and destroyed, the storm later came to be known as The Storm of the Emperor's Wrath.
After Vandire's defeat the Frateris Templar was fully disbanded and the Ecclesiarchy was barred from ever holding any men under arms again, this led to the formation of the Adepta Sororitas; The Sisters of Battle.