Historical clue formulations

• The Once-___ (Seuss character) — 2012-09-14
• Celtic sea god — 2010-12-01
• Celtic sea god — 2009-10-30
• Celtic Neptune — 2005-01-30
• Celtic sea god — 2001-08-08
• Personification of the sea, in myth — 1999-08-08
• Celtic Neptune — 1998-08-16
• Celtic sea god — 1998-04-25
• Celtic Poseidon — 1996-12-29
• Celtic Neptune — 1995-07-20
• Celtic Neptune — 1995-01-29
• Manannan's father, in myth — 1994-10-29
• Celtic Neptune — 1994-07-18