Early life Guido was born sometime between 990 and 999. This birthdate range was conjectured from a now lost and undated manuscript of the
Micrologus, where he stated that he was age 34 while
John XIX was
pope (1024–1033). Swiss musicologist dating of the manuscript to 1025–1026 is agreed by scholars
Claude V. Palisca, Dolores Pesce and Angelo Mafucci, with Mafucci noting that it is "now unanimously accepted". This would suggest a birthdate of . Guido's birthplace is even less certain, and has been the subject of much disagreement between scholars, with music historian Cesarino Ruini noting that due to Guido's pivotal significance "It is understandable that several locations in Italy claim the honor of having given birth to G[uido]". There are two principal candidates:
Arezzo,
Tuscany or the
Pomposa Abbey on the
Adriatic coast near
Ferrara. Musicologist asserted that he was born in Pomposa due to his strong connection with the Abbey from ; according to Van Waesberghe, Guido's
epitaph 'of Arezzo' is because of his stay of about a dozen years there later in life. Disagreeing with Van Waesberghe's conclusions, Mafucci argued that were Guido born in Pomposa, he would have spent nearly 35 years there and would thus more likely be known as 'of Pomposa'. Mafucci cites the account of the near-contemporary historian
Sigebert of Gembloux (–1112) who referred to Guido as "Guido Aretinus" (Guido of Arezzo), suggesting that the early use of such a designation means Guido's birthplace was Arezzo. Citing recently unearthed documents in 2003, Mafucci identified Guido with a
Guido clerico filius Roze of the
Arezzo Cathedral. If Mafucci is correct, Guido would have received early musical education at the Arezzo Cathedral from a
deacon named Sigizo and was ordained as a
subdeacon and active as a
cantor.
Pomposa Around 1013 Guido went to the Pomposa Abbey, one of the most famous
Benedictine monasteries of the time, to complete his education. Becoming a noted monk, he started to develop the novel principles of
staff notation (music being written and read from an organized visual system). Likely drawing from the writings of , Guido began to draft his system in the
antiphonary Regulae rhythmicae, which he probably worked on with his colleague Michael of Pomposa. In the prologue to the antiphonary, Guido expressed his frustration with the large amount of time singers spent to memorize music. The system, he explained, would prevent the need for memorization and thus permit the singers extra time to diversify their studies into other prayers and religious texts. He began to instruct his singers along these lines and obtained a reputation for being able to teach substantial amounts of music quickly. Though his ideas brought interest from around Italy, they inspired considerable jealousy and resistance from his fellow monks, who felt threatened by his innovations. Among those disapproving was ., an
Abbot. In light of these objections, Guido left Pomposa in around 1025 and moved to—or 'returned to', if following the Arezzo birthplace hypothesis—Arezzo.
Arezzo, Rome and later life , depicted in an 11th-century medieval manuscript Arezzo was without a monastery; Bishop Tedald of Arezzo (Bishop from 1023 to 1036) appointed Guido to oversee the training of singers for the Arezzo Cathedral. It was at this time that Guido began work on the
Micrologus, or in full
Micrologus de disciplina artis musicae. The work was both commissioned by and dedicated to Tedald. It was primarily a musical manual for singers and discussed a wide variety of topics, including chant,
polyphonic music, the
monochord,
melody,
syllables,
modes,
organum,
neumes and many of his teaching methods. Resuming the same teaching approach as before, Guido lessened the standard 10-year training for the ideal cantor to only one or two years. Italy-wide attention returned to Guido, and Pope John XIX called him to
Rome, having either seen or heard of both his
Regulae rhythmicae and innovative staff notation teaching techniques. Theobald may have helped arrange the visit, and in around 1028, Guido traveled there with the
Canon Dom Peter of Arezzo as well as the Abbot Grimaldus of Arezzo. His presentation incited much interest from the
clergy and the details of his visit are included in the
Epistola ad Michaelem. While in Rome, Guido became sick and the hot summer forced him to leave, with the assurance that he would visit again and give further explanation of his theories. In the
Epistola ad Michaelem, Guido mentions that before leaving, he was approached by the Abbot Guido of Pomposa who regretted his part in Guido's leave from Arezzo and thus invited him to return to the Abbey. Guido of Pomposa's rationale was that he should avoid the cities, as most of their churchmen were accused of
simony, though it remains unknown if Guido chose the Pomposa Abbey as his destination. It seems more likely that around 1029, Guido settled in a monastery of the Avellana of the
Camaldolese order near Arezzo, as many of the oldest manuscripts with Guidonian notation are Camaldolese. The last document pertaining to Guido places him in Arezzo on 20 May 1033; his death is only known to have been sometime after that date. ==Music theory and innovations==