One of the strangest coincidences of modern musical theatre is the fact that its two foremost composers, Andrew Lloyd Webber and Stephen Sondheim, share a birthday, March 22.

Also by coincidence, both are currently working on problematic new musicals that are or were developed in Washington DC, and both of which postponed planned June 1997 openings.

Webber, recently created Lord Lloyd-Webber of Sydmonton by Queen Elizabeth II, was born in 1948, and thus will turn 50 Sunday. On April 7 Elaine Paige will be one of the many stars celebrating his 50th in song at the Royal Albert Hall.

Lloyd Webber is in the middle of rewriting his latest musical, Whistle Down the Wind, which closed in Washington DC in February 1997, cancelling its planned June 1997 Broadway opening. It's now scheduled to open at the Aldwych Theatre in London July 1, 1998. He said this week that he's then taking three months off to work on the sequel, Phantom II.

Sondheim, who lives in New York, was born in 1930, meaning he'll celebrate his 68th birthday Sunday. He is heading down to Washington DC for a developmental workshop of his forthcoming musical, Wise Guys, which has a libretto by John Weidman. A planned June 1996 production at the Kennedy Center has been postponed several times, and now is tenatively aiming at the 1998-99 season. HBO confirmed this week that it's developing Assassins for the cable service.