Proof that the college was the one that started the war? Considering Vivienne is the one who starts the war in divine Leliana ending and the Cassandra conscripted Mage ending has her do everything to silence any pro freedom opinions, I'm certain Vivienne is the one who starts the war.
There is no war in the Leliana ending and there is no war in the Concripted/Divine Cass, please show me otherwise.
I'm talking about this one (mages allied and Divine
Cass):
Some believed that the end of the Inquisition as it had been heralded the destruction of the fledgling College of Enchanters. Having clashed against the Circle, the College now found itself without support against the newly elected Grand Enchanter, Vivienne. Fortunately, Grand Enchanter Vivienne grudgingly agreed not to destroy its terrified leaders, as a personal favor to Divine Victoria.