InWestern classical music, thecommon practice period (CPP) was the period of about 250 years during which thetonal system was regarded as the only basis for composition. It began when composers' use of the tonal system had clearly superseded earlier systems, and ended when some composers began using significantly modified versions of the tonal system, and began developing other systems as well. Most features ofcommon practice (the accepted concepts of composition during this time) persisted from the mid-Baroque period through theClassical andRomantic periods, roughly from 1650 to 1900. There was much stylistic evolution during these centuries, with patterns and conventions flourishing and then declining, such as thesonata form. The most prominent unifying feature throughout the period is aharmonic language to whichmusic theorists can today applyRoman numeral chord analysis; however, the "common" in common practice does not directly refer to any type of harmony, rather it refers to the fact that for over two hundred years only one system was used.

The harmonic language of this period is known as "common-practicetonality", or sometimes the "tonal system" (though whether tonality implies common-practice idioms is a question of debate). Common-practice tonality represents a union between harmonic function andcounterpoint. In other words, individual melodic lines, when taken together, express harmonic unity and goal-oriented progression. In tonal music, each tone in thediatonic scale functions according to its relationship to the tonic (the fundamental pitch of the scale). While diatonicism forms the basis for the tonal system, the system can withstand considerablechromatic alteration without losing its tonal identity.

Throughout the common-practice period, certain harmonic patterns span styles, composers, regions, and epochs.Johann Sebastian Bach andRichard Strauss, for instance, may both write passages that can be analysed according to the progression I-ii-V-I, despite vast differences in style and context. Such harmonic conventions can be distilled into the familiarchord progressions with which musicians analyse and compose tonal music.

Various popular idioms of the twentieth century differ from the standardizedchord progressions of the common-practice period. While these later styles incorporate many elements of the tonal vocabulary (such as major and minor chords), the function of these elements is not identical to classical models of counterpoint and harmonic function. For example, in common-practice harmony, amajor triad built on the fifthdegree of the scale (V) is unlikely to progress directly to aroot position triad built on the fourth degree of the scale (IV), but the reverse of this progression (IV–V) is quite common. By contrast, the V–IV progression is readily acceptable by many other standards; for example, this transition is essential to the"shuffle" blues progression's last line (V–IV–I–I), which has become the orthodox ending forblues progressions at the expense of the original last line (V–V–I–I).^[1]

Coordination of the various parts of a piece of music through an externalized metre is a deeply rooted aspect of common-practice music.Rhythmically, common practicemetric structures generally include:^[2]

1. Clearly enunciated or impliedpulse at all levels, with the fastest levels rarely being extreme
2. Metres, orpulse groups, in two-pulse or three-pulse groups, most often two
3. Metre and pulse groups that, once established, rarely change throughout asection orcomposition
4. Synchronous pulse groups on all levels: all pulses on slower levels coincide with strong pulses on faster levels
5. Consistenttempo throughout a composition or section
6. Tempo, beat length, and measure length chosen to allow onetime signature throughout the piece or section

Durational patterns typically include:^[3]

1. Small or moderate duration complement and range, with one duration (orpulse) predominating in the duration hierarchy, are heard as the basic unit throughout a composition. Exceptions are most frequently extremely long, such aspedal tones; or, if they are short, they generally occur as the rapidly alternating or transient components oftrills,tremolos, or otherornaments.
2. Rhythmic units are based onmetric orintrametric patterns, though specificcontrametric orextrametric patterns are signatures of certain styles or composers.Triplets and other extrametric patterns are usually heard on levels higher than the basic durational unit or pulse.
3. Rhythmic gestures of a limited number of rhythmic units, sometimes based on a single or alternating pair.
4. Thetic (i.e., stressed),anacrustic (i.e., unstressed), and initial rest rhythmic gestures are used, with anacrustic beginnings and strong endings possibly most frequent and upbeat endings most rare.
5. Rhythmic gestures are repeated exactly or invariation after contrasting gestures. There may be one rhythmic gesture almost exclusively throughout an entire composition, but complete avoidance of repetition is rare.
6. Composite rhythms confirm the metre, often in metric or even note patterns identical to the pulse on specific metric level.

Patterns ofpitch andduration are of primary importance in common practicemelody, whiletone quality is of secondary importance. Durations recur and are often periodic; pitches are generally diatonic.^[4]

• Harbison, John (1992). "Symmetries and the 'New Tonality'".Contemporary Music Review.6 (2):71–79.doi:10.1080/07494469200640141.
• Kliewer, Vernon (1975). "Melody: Linear Aspects of Twentieth-Century Music". InAspects of Twentieth-Century Music, edited by Gary Wittlich, pp. 270–301. Englewood Cliffs, New Jersey: Prentice-Hall.ISBN 0-13-049346-5.
• Konečni, Vladimir J. (2009)."Mode and Tempo in Western Classical Music of the Common-Practice Era"(PDF).Empirical Musicology Review.doi:10.18061/1811/36604.hdl:1811/36604. Archived fromthe original(PDF) on 5 March 2016. Retrieved17 February 2015.
• London, Justin (2001). "Rhythm, §II: Historical Studies of Rhythm".The New Grove Dictionary of Music and Musicians, second edition, edited byStanley Sadie andJohn Tyrrell. London: Macmillan Publishers.
• Perle, George (1990).The Listening Composer. Berkeley and Los Angeles: University of California Press.ISBN 0-520-06991-9.
• Tanner, Paul, and Maurice Gerow (1984).A Study of Jazz. Dubuque, Iowa: William C. Brown Publishers. Cited in Robert M. Baker, "A Brief History of the Blues".TheBlueHighway.com.
• Winold, Allen (1975). "Rhythm in Twentieth-Century Music". InAspects of Twentieth-Century Music, edited by Richard Peter Delone and Gary Wittlich, Englewood Cliffs, New Jersey: Prentice-Hall.ISBN 978-0-13-049346-0. pp. 208-269.

• Benjamin Piekut,"No Common Practice: The New Common Practice and its Historical Antecedents" (February 1, 2004).