GUIDO OF AREZZO, an Italian monk of the 11th century, has by many been called the father of modern music, and a portrait of him in the refectory of the monastery of Avellana bears the inscription " Peatus Guido, inventor musicm." Although these statements are manifestly exaggerated, it is none the less true that Guide's reforms mark an enormous progress in the notation as well as in the teaching of music. Of his life little is known, and that little is chiefly derived from the dedicatory letters prefixed to two of his treatises and addressed respectively to Bishop Theodald (not Theobald, as Burney writes the name) of Arezzo, and Michael, a monk of Pomposa. and Guido's pupil and friend. Occasional references to the celebrated musician in the works of Ins contemporaries are, however, by no means rare, and front these it may be conjectured with all but absolute certainty that Guido was born in the last decade of the 10th century. The place of his birth is, beyond a doubt, Arezzo ; for on the title-page of all his works he is styled Guido Aretinus, or simply A reti7,2/8. At his first appearance in history Guido was a monk in the Benedictine monastery of Pomposa, and it was there that lie invented his educational method, by means of which, according to his own statement, a pupil might learn within five months what formerly it would have taken him ten years to acquire. Envy and jealousy, however, were his only reward, and by these he was compelled to leave his monastery - " inde est, quod me vides prolixis finilms exulatum," as he says himself in the second of the letters above referred to. According to one account, he travelled as far as Bremen, called there by Archbishop Hermann in order to reform the musical service. But this statement has been doubted, for chronological and other reasons.

Certain it is that not long after his flight from Pomposa Guido was living at Arezzo, and it was here that, about 1030, he received an invitation to Rome from Pope John XIX. He obeyed the summons, and the pope himself became his first and apparently one of his most proficient pupils. But ia spite of his success Guido could not be induced to remain in Rome, the insalubrious air of which seems to have affected his health. In Rome he met again his former superior, the abbot of Pomposa, who seems to have repented of his conduct towards Guido, and to have induced him to return to Pomposa; and here all authentic records of Guido's life cease. We only know that he died, on May 17, 1050, as prior of Aveliana, a monastery of the Camaldulians ; such at least is the statement o.! the chroniclers of that order. It ought, however, to be added that the almaldulians claim the celebrated musician as wholly their Awn, and altogether deny his connexion with the Benedictines. It is quite in accordance with the semi-mythical character of Guido's life that a great many inventions belonging to earlier as well as to later times have been attributed to him, in the same way as Charlemagne, Arthur, and Roland have been made responsible for the deeds and exploits of other kings and heroes. His eulogists declare that before him church mesh, was in a state of utter barbarism, wholly ignoring the achievements of Gregory the Great, Hucbald, an I others. The notation of music by means of the neunme also, although very imperfect for practical purposes, at any rate served to give permanence to the composer's thoughts. Thera is, however, no doubt that in the latter respect Guido's method shows an enormous progress. It was he who invented, or at least for the first time systematically used, the lines of the staff, and the intervals or spatia between them, and thus fixed the principle of modern notation ; and the value of this innovation for educational and general artistic purposes cannot be overrated. There is also little doubt that the names of the first six notes of the scale, at, re, fa, sd, la, still in use among Romance nations, were introduced by Guido, although he seems to have used them in a relative rather than in an absolute sense, It is well known that these words are the first syllables of six lines of a hymn addressed to St John the Baptist, which may be given here : - Ut pima laxis resonare fibeis Mira gestornin famuli tuorum, Solve polluti /abii rectum, Sanete Joaunes.

In addition to this Guido is generally credited with the introduction of the F clef. But perbal s more itaportant than all this is the thoroughly practical tone which Guido assumes in his theoretical writings, and which differs greatly from the clumsy scholasticism of his contemporaries and predecessors, The most important of Guido's treatises, and those which are gmerally acknowledged v., be anthentic, are Micro&gas Guidonis de diselplina antis musietc, dedicated to Bishop Theodald of Arezzo, and comprising a complete theory of music, in 20 chapters ; Musiece G regahc rhuthaticee in aatiphonarii sui prologam prolake, written in troelmic aecasyllabics of anything but classical structure; Alice Gaidinis •egal,e de ignoto main, identidein ice aatiphonarii sui prolopm prolatx; and the Epistola Gaidonis Michaeli monaeho de ijaoto cacc u, alrea ly referred to. These are published in the second volume of G.Ibert's Scriptores eeelesiastiei de musica &via. A very important manuscript unknown to Gerbert (the Codex, Bibliothecce Uticeasis, in the Paris library) contains. besides minor treatises, an antiphonariunt and gradual undoubtedly belonging to Guido. A exnpreliensive but very uncritical life of Guido has been written by Luigi Angeloni (Sopra be vita, a•c., di Guido cl'Arezzo). Of infinitely greater import-ince are the studies on the subject by Herr Kie•wetter and by H. Bottle de Touhnon. Burney's General History of Masie, and Fetis's Biographic des Mnsiciens should also be consulted. A comprehensive and admirable account of Guido's life awl work by Dr W. Laughans may be found in the fourth volume of 31,mdel's Masikalisehes Conversations.Lezikon.