Complex sentence: At the 19th Congress Molotov and Anastas Mikoyan were said by Stalin to have committed grave mistakes, including the publication of a wartime speech by Winston Churchill favourable to the Soviet Union's war time efforts.
Split into simpler sentences: At the 19th Congress Molotov and Anastas Mikoyan were told by Stalin to have committed grave mistakes. Notable mistakes including the publishing of a wartime speech by Winston Churchill favourable to the Soviet Union's war time efforts.