The main reason why Stalin wanted Britain and he United States to open a second front in France is because for much of the beginning of the war, Russia was fighting Germany on the ground almost completely alone and suffering great losses.
He is so rude because he is probably jealous of Harry, because Harry is more popular and powerful than him.
By 640, they had brought all of Mesopotamia, Syria and Palestine under the control of the Rashidun Caliphate
Ending slavery means it will stop for sure, mean while ending the slavery trade means you won't be making more trades but slavery still exist.
Hope this helps! :)
