Calculus is one thing. In depth study of Middle Eastern history is another. Having taken both at the same time I'd say Calculus is a pud course ~ 10 minutes of study a day MAX! ME History required refurbishing reading knowledge of Spanish and French, and studying the geography of the entire Moslem World ~ and that was just to keep up with the guy teaching the course ~ the world's foremost expert concerning the Kurds.
It was a bear and a half, and all the people in the course worked for Air Force intelligence ~ except me!
Anybody can throw a bunch of facts at you and expect you to memorize them all. It’s the concepts that make it difficult.
And if calc is difficult, how can somebody be expected to do complex analysis?