Tempus, Lord of Battles
Tempus, also known as the Lord of Battles, is the god of war. His dogma is primarily concerned with honorable battle, forbidding cowardice and encouraging the use of force of arms to settle disputes.
Faerûn is a violent land, and thus from sheer number of worshipers Tempus is one of the mightiest deities in the Realms. Nearly everyone who draws a sword or notches an arrow has fought alongside a cleric of the Foehammer, and just as many fought against one.
Due to its tendency to have followers and priests on both sides of any engagement, the Church of Tempus has no central authority that might support one side or the other exclusively. Within a given temple or order, however, there is a strict hierarchy and chain of command.