Complex sentence: It is unknown if Dave Mustaine or any other Megadeth members attended these ceremonies, Also on July 25 of 1999 Dave Mustaine dedicated Peace Sells in his memory on the Woodstock Festival.
Split into simpler sentences: It is unknown if Mustaine or any other Megadeth members attended these ceremonies. On July 25,1999, lead vocalist Mustaine dedicated Peace Sells to his memory, on the Woodstock Festival.