Historical clue formulations

• *Longest resident performer at the Colosseum at Caesars Palace — 2021-09-06
• #1 Billboard artist that's an anagram of 23-Across — 2015-08-23
• Singer whose first top 10 hit was "Where Does My Heart Beat Now" — 2013-12-06
• *1996 Grammy winner for the album "Falling Into You" — 2010-09-22