The Classical period in Western music occurred from about 1750 to 1810, despite considerable overlap at both ends with preceding and following periods, as is true for all musical eras. Although the term classical music is used as a blanket term meaning all kinds of music that do not fall into the 'popular' idiom of the 20th and 21st centuries, it can also occasionally mean this particular era of time.

The Classical period falls between the Baroque and the Romantic periods. The best known composers from this period are Joseph Haydn, Wolfgang Amadeus Mozart and Ludwig van Beethoven; other notable names include Luigi Boccherini, Muzio Clementi, and Christoph Willibald Gluck. Beethoven is also sometimes regarded either as a Romantic composer or a composer who was part of the transition to the Romantic; Franz Schubert is also something of a transitional figure, as are Johann Nepomuk Hummel, Luigi Cherubini and Carl Maria von Weber.

In the seventeenth and early eighteenth centuries, one country had been musically dominant. The lead of Italy contributed greatly towards the cultural life of Europe, with Italian musical influence spreading as far afield as Ireland. With the birth of the classical era, a single city, Vienna, was to rise to prominence and become the musical capital for the next hundred years. The sheer number of important musicians who have been natives or inhabitants of Vienna is most significant and number 100 or more.

In the middle of the 18th century, Europe began to move to a new style in architecture, literature, and the arts generally, known as Classicism. While still tightly linked to the court culture and absolutism, with its formality and emphasis on order and hierarchy, the new style was also a cleaner style, one that favored clearer divisions between parts, brighter contrasts and colors, and simplicity rather than complexity. This taste for structural clarity worked its way into the world of music as well, moving away from the layered polyphony (a texture consisting of two or more independent melodic voices) (hear sample ) of the Baroque period, and towards a style where a melody over a subordinate harmony – a combination called homophony – (hear sample ) was preferred. This meant that playing of chords, even if they interrupted the melodic smoothness of a single part, became a much more prevalent feature of music, and this in turn made the tonal structure of works more audible.

The new style was also pushed forward by changes in the economic order and in social structure. As the 18th century progressed, the nobility more and more became the primary patrons of instrumental music, and there was a rise in the public taste for comic opera. This led to changes in the way music was performed, the most crucial of which was the move to standard instrumental groups, and the reduction in the importance of the continuo – the harmonic fill beneath the music, often played by several instruments. One way to trace this decline of the continuo and its figured chords is to examine the decline of the term obbligato, meaning a mandatory instrumental part in a work of chamber music. In the Baroque world, additional instruments could be optionally added to the continuo; in the Classical world, all parts were noted specifically, though not always notated, as a matter of course, so the word "obbligato" became redundant. By 1800, the term was virtually extinct, as was the practice of conducting a work from the keyboard.

The changes in economic situation just noted also had the effect of altering the balance of availability and quality of musicians. Music became middle class, and so did the musicians, and to be in public favour was to be duly rewarded for it. The idea of fame and a celebrated name was to beginning to grow, and have a direct impact on the life of the composer. The rewards for fame included greater income from published music for the middle class to play, and involvement in the most upper class households extending to even Royalty. In addition, the appetite for a continual supply of new music, carried over from the Baroque, meant that works had to be performable with, at best, one rehearsal. Indeed, even after 1790 Mozart writes about "the rehearsal", with the implication that his concerts would have only one.

Since polyphonic texture was no longer the focus of music, but rather a single melodic line with accompaniment, there was greater emphasis on notating that line for dynamics and phrasing. The simplification of texture made such instrumental detail more important, and also made the use of characteristic rhythms, such as attention-getting opening fanfares, the funeral march rhythm, or the minuet genre, more important in establishing and unifying the tone of a single movement.

This led to the Classical style's gradual breaking with the Baroque habit of making each movement of music devoted to a single affect (emotion or mood). Instead, it became the style to establish contrasts between sections within movements, giving each its own emotional coloring, using a range of techniques: opposition of major and minor; strident rhythmic themes in opposition to longer, more song-like themes; and especially, making movement between different harmonic areas the principal means of creating dramatic contrast and unity. Transitional episodes became more and more important, as occasions of surprise and delight. Consequently composers and musicians began to pay more attention to these, highlighting their arrival, and making the signs that pointed to them both more audible and more the subject of "play" and subversion. That is, composers more and more created false expectations, only to have the music skitter off in a different direction.

The musical gift to the classical period was 'sonata form'. The previous period saw the sonata as a one movement piece, this was expanded in the classical era to be a specific structured form of first movement, with two or three more movements of another structured form, making up a three to four movement work for solo instrument . Whilst three movements usually apply to solo instrument sonatas, sonata form is also applied to the symphony which usually has four movements. The majority of Haydn's and Mozart's sonatas and chamber music and symphonies are written in this form, and by the end of this period Beethoven had written more than three quarters of his works using sonata form.

Until the middle of the seventeenth century the orchestra as we know it today did not exist. Rich noblemen had their own bands (which could be quite big), but groups of bowed viols competed unsuccessfully with trumpets and drums. Scoring was not often attempted. Until the death of Bach and Handle, conducting was done from the central harpsichord.Johann Stamitz evolved the Mannheim Orchestra into something like the present day chamber orchestra, which is about half the strength of today's symphony orchestra (see modern layout). He and CPE Bach developed the orchestra by writing new works for it to play, experimenting with new ideas and combinations of instrumental sounds. With the completion of the "Eroica" Symphony in 1804, more than twice as long as any comparable orchestral work before it, the pattern for the nineteenth century was set.

The old order lingered on at the start of the Classical Age. Bach and Handel were still composing fugues when Haydn was in his eighteenth year. At the end of the period, Beethoven’s “Eroica” symphony ( listen to sample now)was performed well within Haydn’s lifetime. The age which connects the St Matthew Passion with Fidelio is little more than half a century long.