Classical music is art music produced or rooted in the traditions of Western music, including both liturgical (religious) and secular music. While a more accurate term is also used to refer to the period from 1750 to 1820 (the Classical period), this article is about the broad span of time from roughly the 11th century to the present day, which includes the Classical period and various other periods.[full citation needed] The central norms of this tradition became codified between 1550 and 1900, which is known as the common-practice period. The major time divisions of Western art music are as follows[clarification needed]: the early music period, which includes the Medieval (500–1400) the Renaissance (1400–1600) eras. Baroque (1600–1750) the common-practice period, which includes Baroque (1600–1750) Classical (1750–1820) Romantic eras (1804–1910) the 20th century (1901–2000) which includes the modern (1890–1930) that overlaps from the late-19th century, the impressionism (1875–1925) that also overlaps from the late-19th century the neoclassicism (1920–1950), predominantly in the inter-war period the experimental (1950–present) the high modern (1950–1969) contemporary (1945 or 1975–present) or postmodern (1930–present) eras. European art music is largely distinguished from many other non-European classical and some popular musical forms by its system of staff notation, in use since about the 16th century.[not in citation given] Western staff notation is used by composers to indicate to the performer the pitches (e.g., melodies, basslines, chords), tempo, metre and rhythms for a piece of music[clarification needed]. This can leave less room for practices such as improvisation and ad libitum ornamentation, which are frequently heard in non-European art music and in popular-music[clarification needed][not in citation given] styles such as jazz and blues. Another difference is that whereas most popular styles adopt the song (strophic) form, classical music has been noted for its development of highly sophisticated forms of instrumental music such as the concerto, symphony, sonata, and mixed vocal and instrumental styles such as opera which, since they are written down, can sustain larger forms and attain a high level of complexity.[clarification needed] The term "classical music" did not appear until the early 19th century, in an attempt to distinctly canonize the period from Johann Sebastian Bach to Beethoven as a golden age. The earliest reference to "classical music" recorded by the Oxford English Dictionary is from about 1836.Opera (Italian: [ˈɔːpera]; English plural: operas; Italian plural: opere [ˈɔːpere]) is an art form in which singers and musicians perform a dramatic work combining text (libretto) and musical score, usually in a theatrical setting. In traditional opera, singers do two types of singing: recitative, a speech-inflected style and arias, a more melodic style, in which notes are sung in a sustained fashion. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble, which since the early 19th century has been led by a conductor. Opera is a key part of the Western classical music tradition. It started in Italy at the end of the 16th century (with Jacopo Peri's mostly lost Dafne, produced in Florence in 1598) and soon spread through the rest of Europe: Heinrich Schütz in Germany, Jean-Baptiste Lully in France, and Henry Purcell in England all helped to establish their national traditions in the 17th century. In the 18th century, Italian opera continued to dominate most of Europe (except France), attracting foreign composers such as George Frideric Handel. Opera seria was the most prestigious form of Italian opera, until Christoph Willibald Gluck reacted against its artificiality with his "reform" operas in the 1760s. In the 2000s, the most renowned figure of late 18th-century opera is Wolfgang Amadeus Mozart, who began with opera seria but is most famous for his Italian comic operas, especially The Marriage of Figaro (Le nozze di Figaro), Don Giovanni, and Così fan tutte, as well as The Magic Flute (Die Zauberflöte), a landmark in the German tradition. The first third of the 19th century saw the high point of the bel canto style, with Gioachino Rossini, Gaetano Donizetti and Vincenzo Bellini all creating works that are still performed. It also saw the advent of Grand Opera typified by the works of Auber and Meyerbeer. The mid-to-late 19th century was a "golden age" of opera, led and dominated by Richard Wagner in Germany and Giuseppe Verdi in Italy. The popularity of opera continued through the verismo era in Italy and contemporary French opera through to Giacomo Puccini and Richard Strauss in the early 20th century. During the 19th century, parallel operatic traditions emerged in central and eastern Europe, particularly in Russia and Bohemia. The 20th century saw many experiments with modern styles, such as atonality and serialism (Arnold Schoenberg and Alban Berg), Neoclassicism (Igor Stravinsky), and Minimalism (Philip Glass and John Adams). With the rise of recording technology, singers such as Enrico Caruso and Maria Callas became known to much wider audiences that went beyond the circle of opera fans. Since the invention of radio and television, operas were also performed on (and written for) these mediums. Beginning in 2006, a number of major opera houses began to present live high-definition video transmissions of their performances in cinemas all over the world. In 2009, an opera company offered an online download of a complete performance.