Chronoforges were devices created by the Time Lords of Gallifrey which were capable of creating weapons of temporal destruction. As a byproduct, they produced light; this was actually the bleeding off of photonic waste from fracturing chronons.
The Eighth Gallifrey of the Nine Gallifreys had Chronoforges and Loomstacks on its surface creating soldiers and weapons for use against The Enemy in the War. (PROSE: The Taking of Planet 5)