In the 17th century guitars were often of different sizes. Several of the early guitar books, notably Corbetta's 1639 book, 'Degli scherzi armonici' include instructions for tuning several guitars so that they can play in consort. Carbonchi's 'Le dodici chitarre spostate' 1643 actually gives instructions for guitars tuned to 12 different pitches. The assumption is that they would play the same music as the standard instrument at a different pitch. The instructions explain how to transpose the alfabeto tablature for this purpose. Foscarini's earliest surviving book 'Intavolatura de chitarra spagnola' printed in 1629 does include 2 pieces for three guitars with the separate parts set out side by side.