One of the earliest instances is found in a sonata by Domenico Scarlatti, K. 544. This is the whole first half of the sonata:
As you can see, in the third staff the music comes to a stop on an ornamented V of V. This is followed by a whole measure of rest with a fermata. (The fermata is that half circle enclosing a dot, which indicates an unmeasured pause.) This prepares a restatement of the theme on the dominant. The same effect is used in the second half, but this time on the dominant to prepare a return to the theme on the tonic. A simple enough effect, but powerful nonetheless because it was not a device used to any extent in this era. I can't think of any other examples! Let's have a listen to hear what the effect sounds like. The harpsichordist is Trevor Pinnock:
Because the silence occurs in a logical place in the phrase structure, we might call this a structural silence, even though it has a dramatic effect. A purely dramatic silence would be one in a less-anticipated place, such as in this symphony by Haydn:
The unsettling pause at the end of the first four measures, along with the piano dynamic, gives this symphony opening an unusual dramatic tension. Let's listen to how that sounds.
In this period there were two typical ways of beginning a symphony for dramatic effect: one was with an adagio opening with perhaps intense harmonies or brass and tympani; the other was to begin with the allegro straightaway, perhaps with a piano phrase answered with a forte one. But to my knowledge, there are no other openings like this one, with its two dramatic silences.
Haydn made even more radical use of silence in his String Quartet op. 33 no. 2. It is nicknamed "The Joke" because he has, at the end of the last movement, six false endings, trying to trick the audience into applauding too soon! Here is that final page:
Audiences nowadays are prepped for this by either the program notes or by commentary from the performers, but imagine when it was first played. I think that the way to play this would be to preserve the joke and not warn anyone! Let's listen. This is a live performance by the Endellion Quartet from our own chamber music festival in 2010 and I was in the audience for this performance. The recording isn't the most professional, but still listenable, I think. The first silence falls at around the 2'29 mark:
One modern master of the silence was Olivier Messiaen. In the first of his Catalogue d'oiseaux, "Le chocard des alpes" (the Alpine chough) he uses silence very effectively. This bird lives and nests at high altitudes. Here is a picture in its usual environment:
Messiaen's Catalogue d'oiseaux is a representation, not only of the sounds of the birds, but also their environment. In "Le chocard des alpes" he captures the immense voids and distances between the mountains by separating each block of music with long silences. In this recording, the first occurs around the 50 second mark. There is another at around the 1:30 mark and many others. I don't intend that you listen to all of this clip, which contains the whole of the nearly three hour piece, but just the first piece (about the first ten minutes). The pianist is Yvonne Loriod:
Inevitably the example of John Cage's 4'33 comes to mind, which is a piece consisting entirely of silence. Ironically, while of considerable philosophical interest, this is of very little musical interest because it is nothing but silence. The musical drama only comes with the skillful juxtaposition of sound and silence.