Historical clue formulations

• Russian revolutionary of the early 1900s — 2026-04-15
• Political figure on whom Snowball is based in "Animal Farm" — 2019-12-15
• Noted Bolshevik — 2003-11-23
• Assassination victim of 1940 — 1998-09-10
• Lev Bronstein's alias — 1998-07-12
• Red Army founder — 1998-04-23