were entirely new compositions. Duke Ellington's and Billy Strayhorn's arrangements for the Duke Ellington big band were usually new compositions, and some of Eddie Sauter's arrangements for the Benny Goodman band and Artie Shaw's arrangements for his own band were new compositions as well. It became more common to arrange sketchy jazz combo compositions for big band after the bop era. After 1950, the big bands declined in number. However, several bands continued and arrangers provided renowned arrangements. Gil Evans wrote a number of large-ensemble arrangements in the late 1950s and early 1960s intended for recording sessions only. Other arrangers of note include Vic Schoen, Pete Rugolo, Oliver Nelson, Johnny Richards, Billy May, Thad Jones, Maria Schneider, Bob Brookmeyer, Lou Marini, Nelson Riddle, Ralph Burns, Billy Byers, Gordon Jenkins, Ray Conniff, Henry Mancini, Ray Reach, Vince Mendoza, and Claus Ogerman. In the 21st century, the big-band arrangement has made a modest comeback. Gordon Goodwin, Roy Hargrove, and Christian McBride have all rolled out new big bands with both original compositions and new arrangements of standard tunes. For instrumental groups Strings The string section is a body of instruments composed of various bowed stringed instruments. By the 19th century orchestral music in Europe had standardized the string section into the following homogeneous instrumental groups: first violins, second violins (the same instrument as the first violins, but typically playing an accompaniment or harmony part to the first violins, and often at a lower pitch range), violas, cellos, and double basses. The string section in a multi-sectioned orchestra is sometimes referred to as the "string choir." The harp is also a stringed instrument, but is not a member of nor homogeneous with the violin family and is not considered part of the string choir. Samuel Adler classifies the harp as a plucked string instrument in the same category as the guitar (acoustic or electric), mandolin, banjo, or zither. Like the harp these instruments do not belong to the violin family and are not homogeneous with the string choir. In modern arranging these instruments are considered part of the rhythm section. The electric bass and upright string bass—depending on the circumstance—can be treated by the arranger as either string section or rhythm section instruments. A group of instruments in which each member plays a unique part—rather than playing in unison with other like instruments—is referred to as a chamber ensemble. A chamber ensemble made