Sequence 1 is a list of the:  
>! **[nine muses][1]** of Greek mythology as follows (bold for missing letters):  
>!  
>!  Calliope, Clio, **Euterpe**, Erato, **Melpomene**, Polyhymnia, Terpsichore, Thalia, **Urania**  
  
Sequence 2 is the order of the:  
>! **[British monarchs][2]** as follows (bold for missing letters):  
>!  
>! Anne, George I, **George II**, George III, **George IV**, William IV, Victoria, Edward VII,  George V, Edward VIII, **George VI**, **Elizabeth II**   
  
Sequence 4 is a list of the:  
>!  **second letters of the abbreviation of US states** (bold for missing letters).    
>!  The order is alphabetical based on the full state name.  
>!   
>! **AL, AK, AZ**, AR, CA, CO, CT, DE, FL, GA, HI, ID, IL, IN, IA, KS, KY, LA, ME, MD...

  [1]: http://en.wikipedia.org/wiki/Muse
  [2]: http://en.wikipedia.org/wiki/List_of_British_monarchs