Historical clue formulations

• Year that Michelangelo's "The Crucifixion of St. Peter" was completed — 2019-12-22
• Year Charles IX was born — 2014-03-14
• The year 1550 — 2012-08-27
• Year of Ronsard's "Odes" — 2011-08-31
• Midcentury year — 2009-04-23
• Roman 1,550 — 2007-01-22
• Year Helsinki was founded — 2003-12-12
• Year in the reign of Ivan the Terrible — 2003-02-15
• Year Helsinki was founded — 2002-11-30
• Start of Julius III's papacy — 2002-07-17
• Year in the reign of Edward VI — 1998-10-08
• Caesar's 1550 — 1995-04-19
• Year Helsinki was founded — 1994-04-30