useless trivia: What Word Means: A Musical Transition?

Questions

In 1699 Russian ---------- adjusted so Russian New Year occurs on January 1st, instead of September 1st. ?

In 1832 Turkey cedes the island of ---------- to the Egyptians. ?

In 1922 Assorted Russian republics form together to found the Union of ---------- Socialist Republics. ?

In 1968 (USA) John---------- , author, died. ?

In 1491 Five year truce between England and ---------- began. ?