Τριάς - Trias in ancient Greek means Trinity, a union of three people or things. The Holy Trinity, the three persons of the Christian Godhead which is an unconceivable union to the human conception is the most famous of them all. Number three is very important in eastern tradition, philosophy and religion as are the other odd numbers, (the most important after three is seven). The number three governs most of the principles of the piece: rhythm, pitch and timbre and also applies to the form.