Salzburg Easter Festival:
"Salzburger Osterfestspiele"

Although the name implies that the Salzburg Easter Festival is an independent institution, it was in fact founded as a supplement to the Salzburg Festival by Herbert von Karajan in 1967. The two festivals have always been tied together and even though the Osterfestspiele have their own traditions and flavour, they remain something like "the little sister" of the Festspiele in the summer.
The core piece of the much shorter Easter Festival is an Opera production in the large Festival Hall, which is performed by the
Berliener Philharmoniker Orchestra. This is another difference to the summer festival that has the Wiener Philharmoniker Orchestra as its key performing orchestra.
Herbert von Karajan remained the head of the Osterfestspiele until he died in 1989. Later Sir Georg Solti and Claudio Abbado were responsible for the performances at the festival, since 2003 this is the office of Sir Simon Rattle.
The Second Music Festival in Salzburg
Critique always hit the Ester Festival for being commercial or a foul trick to attract wealthy crowds during an otherwise rather lame season. This might well be the case, but at least the crowds come for a good reason.
Much like the Salzburger Festspiele during the summer months, the Osterfestspiele bring together some of the World′s most professional singers, musicians and dramatists to perform opera on a level as good as it gets pretty much anywhere in the World.
If you are interested in the schedules of the Easter Festival or want to purchase any particular tickets, you can use the same facilities as for the Festspiele; ticket offices are generally more expensive than the box offices of the Festival. The tourist information office will be able to advise you and you might even be able to book packages for you.
Links
http://www.osterfestspiele-salzburg.at/en/
Official
Website Salzburg Easter Festival
http://en.wikipedia.org/wiki/Herbert_von_Karajan
Wikipedia on Herbert von Karajan, founder of the Easter Festival