tracts on musical theory, including the cosmological connotations of music. He identified twelve tones on the Arabic musical scale, based on the location of fingers on and the strings of the oud. Abulfaraj (897–967) wrote the Kitab al-Aghani, an encyclopedic collection of poems and songs that runs to over 20 volumes in modern editions. Al-Farabi (872–950) wrote a notable book on Islamic music titled Kitab al-Musiqa al-Kabir (The Great Book of Music). His pure Arabian tone system is still used in Arabic music. Al-Ghazali (1059–1111) wrote a treatise on music in Persia which declared, "Ecstasy means the state that comes from listening to music". In 1252, Safi al-Din developed a unique form of musical notation, where rhythms were represented by geometric representation. A similar geometric representation would not appear in the Western world until 1987, when Kjell Gustafson published a method to represent a rhythm as a two-dimensional graph. Al-Andalus By the 11th century, Islamic Iberia had become a center for the manufacture of instruments. These goods spread gradually throughout France, influencing French troubadours, and eventually reaching the rest of Europe. The English words lute, rebec, and naker are derived from Arabic oud, rabab or Maghreb rebab, and naqareh. 16th to 19th century Bartol Gyurgieuvits (1506–1566) spent 13 years as a slave in the Ottoman empire. After escaping, he published De Turvarum ritu et caermoniis in Amsterdam in 1544. It is one of the first European books to describe music in Islamic society. 20th century–present Egypt and the Levant In the early 20th century, Egypt was the first in a series of Arab countries to experience a sudden emergence of nationalism, as it became independent after 2000 years of foreign rule. Any English, French or European songs got replaced by national Egyptian music. Cairo became a center for musical innovation. Female singers were some of the first to take a secular approach. Egyptian performer Umm Kulthum and Lebanese singer Fairuz were notable examples of this. Both have been popular through the decades that followed and both are considered legends of Arabic music. Across the Mediterranean, Moroccan singer Zohra Al Fassiya was the first female performer to achieve wide popularity in the Maghreb region, performing traditional Arab Andalusian folk songs and later recording numerous albums of her own. During the 1940s and 1960s, Arabic music began to take on a more Western tone – Egyptian artists Umm Kulthum and Abdel Halim