Epic History
Epic History tells big stories at length, and its recent films show the range: the First Crusade, Waterloo and the Hundred Days, and the Dutch raid on the Medway in 1667, billed as England's greatest naval disaster. The channel says its team holds history degrees and works with specialist historians, and the narration stays measured even on the most dramatic subjects.
That combination makes it one of the best starting points for broad military and political history. Video descriptions seldom list sources, though, so it suits overview viewing better than citation.
More about Epic History