received the necessary training and development. Schools similar to that at Rome were established at all the great cathedrals and the Roman system of musical instruction was thus spread over the entire church. Throughout the Middle Ages musical learning and culture--what little there was of them--were the exclusive property of the church, and the only centres of musical instruction were the choir schools. Every advance which music made during these centuries involved an extension of the art of singing, and this necessitated of course a corresponding progress of the art of vocal training. Progress was painfully slow; indeed little can be pointed out as marking any distinct advance until the invention of the _sol-fa_ system of instruction by Guido d’Arezzo about the year 1100.[4] On the basis of this system an entirely new form of musical education was erected, which continued to flourish until well along in the 17th century. The new system of musical instruction consisted of what we should now call a training in sight singing. The first method of vocal culture worthy the name was a natural outgrowth of the _sol-fa_ system. Students were trained in a knowledge of the intervals by singing the _ut_, _re_, _mi_ syllables in different combinations. Choir masters were not slow to observe that this form of study offered excellent means for acquiring a command of the voice. With the exception of the first one, _ut_, all the _sol-fa_ syllables are sonorous and easily sung. The difficulty attached to the singing of _ut_ was obviated by substituting for it the syllable _do_. Constant singing of the syllables was found to have an admirable effect on the voice, and they were soon adopted as the basis of vocal instruction. _Sol-fa_ practice was made to serve a double purpose; both the ear and the voice received the due measure of attention. Vocal training was not at this time, nor indeed for several centuries later, thought to require any very close attention. It was simply an incident in the general musical education. The demands made on the voice were slight in comparison with the requirements of the music of a few centuries later. Music had long been strictly unisonic in character, but about the time of Guido the need of some addition to a single melody began to be noted.