Editing Gregorian chant (section)

===Dissemination and hegemony===
Gregorian chant appeared in a remarkably uniform state across Europe within a short time. [[Charlemagne]], once elevated to [[Holy Roman Emperor]], aggressively spread Gregorian chant throughout his empire to consolidate religious and secular power.{{sfn|Wilson|1990|p=10}} From English and German sources, Gregorian chant spread north to [[Scandinavia]], [[Iceland]] and [[Finland]].{{sfn|Hiley|1995|p=604}} In 885, [[Pope Stephen V]] banned the [[Church Slavonic language|Slavonic]] liturgy, leading to the ascendancy of Gregorian chant in Eastern Catholic lands including [[Poland]], [[Moravia]] and [[Slovakia]].

The other plainchant repertories of the Christian West faced severe competition from the new Gregorian chant. Charlemagne continued his father's policy of favoring the Roman Rite over the local Gallican traditions. By the 9th century the Gallican rite and chant had effectively been eliminated, although not without local resistance.{{sfn|Apel|1990|p=80}} The Gregorian chant of the [[Sarum Rite]] displaced [[Celtic chant]]. Gregorian coexisted with Beneventan chant for over a century before Beneventan chant was abolished by papal decree (1058). Mozarabic chant survived the influx of the [[Visigoths]] and [[Moors]], but not the Roman-backed prelates newly installed in Spain during the [[Reconquista]]. Restricted to a handful of dedicated chapels, modern Mozarabic chant is highly Gregorianized and bears no musical resemblance to its original form. Ambrosian chant alone survived to the present day, preserved in [[Milan]] due to the musical reputation and ecclesiastical authority of [[Ambrose|St. Ambrose]].

Gregorian chant eventually replaced the local chant tradition of Rome itself, which is now known as Old Roman chant. In the 10th century, virtually no musical manuscripts were being notated in Italy. Instead, Roman Popes imported Gregorian chant from (German) Holy Roman Emperors during the 10th and 11th centuries. For example, the [[Credo]] was added to the [[Roman Rite]] at the behest of the Emperor [[Henry II, Holy Roman Emperor|Henry II]] in 1014.{{sfn|Hoppin|1978a|p=47}} Reinforced by the legend of Pope Gregory, Gregorian chant was taken to be the authentic, original chant of Rome, a misconception that continues to this day. By the 12th and 13th centuries, Gregorian chant had supplanted or marginalized all the other Western plainchant traditions.

Later sources of these other chant traditions show an increasing Gregorian influence, such as occasional efforts to categorize their chants into the Gregorian [[mode (music)|modes]]. Similarly, the Gregorian repertory incorporated elements of these lost plainchant traditions, which can be identified by careful stylistic and historical analysis. For example, the ''[[Improperia]]'' of [[Good Friday]] are believed to be a remnant of the Gallican repertory.{{sfn|Parrish|1986|pp=8–9}}