<P> The polyphonic singing tradition of Epirus is a form of traditional folk polyphony practiced among Aromanians, Albanians, Greeks, and Macedonian Slavs in southern Albania and northwestern Greece . This type of folk vocal tradition is also found in the Republic of Macedonia and Bulgaria . Albanian polyphonic singing can be divided into two major stylistic groups as performed by the Tosks and Labs of southern Albania . The drone is performed in two ways: among the Tosks, it is always continuous and sung on the syllable' e', using staggered breathing; while among the Labs, the drone is sometimes sung as a rhythmic tone, performed to the text of the song . It can be differentiated between two -, three - and four - voice polyphony . </P> <P> The phenomenon of Albanian folk iso - polyphony (Albanian iso - polyphony) has been proclaimed by UNESCO a "Masterpiece of the Oral and Intangible Heritage of Humanity". The term iso refers to the drone, which accompanies the iso - polyphonic singing and is related to the ison of Byzantine church music, where the drone group accompanies the song . </P> <P> Polyphony in the Republic of Georgia is arguably the oldest polyphony in the Christian world . Georgian polyphony is traditionally sung in three parts with strong dissonances, parallel fifths, and a unique tuning system based on perfect fifths . Georgian polyphonic singing has been proclaimed by UNESCO an Intangible Cultural Heritage of Humanity . Polyphony plays a crucial role in Abkhazian traditional music . Polyphony is present in all genres where the social environment provides more than one singer to support the melodic line . Readers might remember (from the very beginning of this book) the recollection of I. Zemtsovsky, when a dozing Abkhazian started singing a drone to support a singer unknown to him . Abkhazian two and three - part polyphony is based on a drone (sometimes a double drone). Two part drone songs are considered by Abkhazian and Georgian scholars the most important indigenous style of Abkhazian polyphony . Two - part drone songs are dominating in Gudauta district, the core region of ethnic Abkhazians . Millennia of cultural, social and economic interactions between Abkhazians and Georgians on this territory resulted in reciprocal influences, and in particular, creation of a new, so - called "Georgian style" of three - part singing in Abkhazia, unknown among Adighis . This style is based on two leading melodic lines (performed by soloists - akhkizkhuo) singing together with the drone or ostinato base (argizra). Indigenous Abkhazian style of three - part polyphony uses double drones (in fourths, fifths, or octaves) and one leading melodic line at one time . Abkhazians use a very specific cadence: tetrachordal downward movement, ending on the interval fourth . </P> <P> Both Chechen and Ingush traditional music could be very much defined by their tradition of vocal polyphony . As in other North Caucasian musical cultures, Chechen and Ingush polyphony is based on a drone . Unlike most of the other North Caucasian polyphonic traditions (where two - part polyphony is the leading type), Chechen and Ingush polyphony is mostly three - part . Middle part, the carrier of the main melody of songs, is accompanied by the double drone, holding the interval of the fifth "around" the main melody . Intervals and chords, used in Chechen and Ingush polyphony, are often dissonances (sevenths, seconds, fourths). This is quite usual in all North Caucasian traditions of polyphony as well, but in Chechen and Ingush traditional songs more sharp dissonances are used . In particular, a specific cadence, where the final chord is a dissonant three - part chord, consisting of fourth and the second on top (c-f-g), is quite unique for North Caucasia . Only on the other side of Caucasian mountains, in western Georgia, there are only few songs that finish on the same dissonant chord (c-f-g). </P>

When did polyphony start to become important for sacred and secular music