Historical clue formulations

• River of Hades — 2022-05-28
• River of forgetfulness, in myth — 2021-09-27
• One of the five rivers of 56-Across — 2019-12-28
• River of forgetfulness, in myth — 2018-07-06
• River of forgetfulness — 2016-09-30
• River of myth where one drinks to forget — 2016-01-30
• River of forgetfulness in Hades — 2013-12-15
• Hades' river of forgetfulness — 2013-01-30
• River of Hades — 2012-06-13
• River that the dead drank from, in myth — 2012-04-13
• River through Hades — 2012-04-02
• River in Hades — 2008-05-30
• River in "The Divine Comedy" — 2007-01-12
• Oblivion — 2007-01-11
• River in Hades — 2005-09-30
• River of oblivion — 2005-06-06
• River in Hades — 2005-05-24
• River of Hades — 2003-11-15
• Oblivion — 2002-07-10
• River in Hades — 2000-11-21
• River in Hades — 1998-05-06
• Oblivion — 1997-08-08
• River of forgetfulness — 1996-12-05
• River of forgetfulness — 1996-08-13
• River of forgetfulness — 1995-07-29
• Underworld river — 1994-11-05