The Battle of Templaria started 1,920 years after the beginning of the War of the Ancients.
The Alliance noted the large number of soldiers, fighters, and support for the Confederacy made in Templaria. They decided to suppress the nation to prevent the creation of these starfighters. The battle eventually began after the Alliance voted for sending a fairly large strike group to the Andromeda I galaxy.
Even though the Templars had a very large population and advanced technology, they were outmatched by the sheer might of The Allaince. Even so, it took eight centuries for the galaxy to be fully occupied.
This made the Templars evacuate every remaining major world in the galaxy. As robots, they were able to do this incredibly efficiently. Several million Templars left the galaxy entirely, but the vast majority boldly remained to fight against the Alliance.
The Templars that left the galaxy fled to intergalactic space. They ended up about 100 million lightyears from the Milky Way, inside of an intergalactic void. There, they waited until a physical Templarian ship were to tell them to come back, or 10000 years would pass, whichever one came first.
The Alliance controlled the entire galaxy for the vast majority of the Battle of Templaria. This battle was mostly a guerilla offensive of Templars trying to be as troublesome as possible for the Alliance. They ended up controlling almost every world in the Andromeda I galaxy. However, this did not stop small resistance groups of Templars from fighting back.
The Templars remaining in the galaxy managed to survive, but were barely managing to maintain several mobile fleets. Over three quadrillion Templars were completely cut off from outside communication, so they hunted harvester ships in groups of up to seven starfighters.
The Templars were able to survive only because Templarian starfighters have a sublime quality. They can outclass almost any drone or human starfighter, as a result of reverse-engineering. They were only able to pick off small amounts of drones, and were eventually a notable nuisance to The Alliance. The starfighters were not perfect, only being able to handle one or two drones by themselves, but they were still good at fending them off.
The strategy of picking off lone ships or drones was mildly effective and did result in an annoying number of casualties for the Alliance, but it also caused The Templars to lose many troops over time. By 190000, the Templars had only about ten million starfighters left in the galaxy. Even if they were in small numbers, they still continued to fight valiantly. By the end of the war, only several hundred starfighters remained in the galaxy.