The more you read on transubstantiation, the more it's history seems kind of sketchy.

It seems like transubstantiation in the RC church does not date back to the Last Supper, but to Paschasius Radbertus, a Benedictine monk, published a treatise openly advocating the doctrine of transubstantiation in 831.

It took about four hundred years to get accepted, at the Fourth Lateran Council in 1215 A.D (after about 176 RC popes sat without it, and around the time of King John and the fourth Crusade), where it was officially defined and canonized as a dogma of the RC church.

Like many of the beliefs and rites of Romanism, transubstantiation was first practiced by pagan religions...source: http://associate.com/library/The_Reading_Room/False_Teaching_n_Teachers_3/Transubstantiation.shtml


Some useful information sites:

http://www.ccel.org/ccel/schaff/hcc4.i.xi.xxi.html


http://www.ianpaisley.org/article.asp?ArtKey=transub