Historical clue formulations

• Russian rulers of old — 2019-07-28
• Bygone sovereigns — 2018-06-01
• Catherine I and others — 2007-12-15
• Winter Palace residents — 2003-12-14
• Queens' Russian counterparts — 2003-04-23
• Russian empresses — 2003-04-22
• Catherine and others — 2001-03-24
• 21-Down and others — 1996-08-11