Simplify the following text for a Grade 5 native English-speaking person.
Original: Dream Theater is an American progressive metal band formed in 1985 under the name Majesty by John Petrucci , John Myung , and former drummer Mike Portnoy while they attended Berklee College of Music in Massachusetts , which they consequently dropped out of to further concentrate on the band which would ultimately become Dream Theater .
Simplified: The band was founded by John Myung , John Petrucci and Mike Portnoy .