Journal of Music Theory was created in 1957.
Dutch Journal of Music Theory was created in 1996.
Music Analysis - journal - was created in 1982.
Leonardo Music Journal was created in 1968.
Journal of Research in Music Education was created in 1953.
Journal of the Society for American Music was created in 1983.
Journal of Music Teacher Education was created in 1991.
Music Theory Spectrum was created in 1979.
Society for Music Theory was created in 1977.
This was created around the same time music was invented. In order to play music at all, you must have good technique, posture...
"Florida State University at Tallahassee: Bachelor of Music Performance in Voice Florida State University's College of Music Voice Area offers bachelor's and graduate degree programs in Music Performance in Voice . Courses in the Bachelor of Music Performance in Voice include vocal pedagogy, vocal and opera literature, music theory, music history, conducting, and opera training. Graduate level courses include pedagogy and vocal and opera literature; graduate students sing in vocal ensembles and in FSU Opera productions. These graduate degree programs include Master of Music Performance in Voice and Doctor of Music in Voice Performance. Students applying for admission to Music Performance in Voice degree programs must first pass a classical singing audition."
I am not sure what music theory you are looking for. Music theory is very vast and required time and practice to know it completely. You can check out some music theory lessons at pianomother and from there you can learn the basic up to the advance lessons for music theory.