criteria used. Through semantic widening, a broader sense of the word "song" may refer to instrumentals, such as the 20th century Songs Without Words pieces for solo piano. Genres Art Art songs are songs created for performance by classical artists, often with piano or other instrumental accompaniment, although they can be sung solo. Art songs require strong vocal technique, an understanding of language, diction, and poetry for interpretation. Though such singers may also perform popular or folk songs on their programs, these characteristics and the use of poetry are what distinguish art songs from popular songs. Art songs are a tradition from most European countries, and now other countries with classical music traditions. German-speaking communities use the term art song ("Kunstlied") to distinguish so-called "serious" compositions from folk songs (Volkslied). The lyrics are often written by a poet or lyricist and the music separately by a composer. Art songs may be more formally complicated than popular or folk songs, though many early Lieder by the likes of Franz Schubert are in simple strophic form. The accompaniment of European art songs is considered as an important part of the composition. Some art songs are so revered that they take on characteristics of national identification. Art songs emerge from the tradition of singing romantic love songs, often to an ideal or imaginary person and from religious songs. The troubadours and bards of Europe began the documented tradition of romantic songs, continued by the Elizabethan lutenists. Some of the earliest art songs are found in the music of Henry Purcell. The tradition of the romance, a love song with a flowing accompaniment, often in triple meter, entered opera in the 19th century and spread from there throughout Europe. It spread into popular music and became one of the underpinnings of popular songs. While a romance generally has a simple accompaniment, art songs tend to have complicated, sophisticated accompaniments that underpin, embellish, illustrate or provide contrast to the voice. Sometimes the accompaniment performer has the melody, while the voice sings a more dramatic part. Folk Folk songs are songs of often anonymous origin (or are public domain) that are transmitted orally. They are frequently a major aspect of national or cultural identity. Art songs often approach the status of folk songs when people forget who the author was. Folk songs are also frequently transmitted non-orally (that is, as sheet music), especially in the modern