History of the Greek alphabet only required one. The history here is complicated, but basically "sāmekh" dropped out in certain dialects, and was reused to represent in others, while usage for the sound varied between "ṣādē" and "šin". The letter now known as sigma took its name from "sāmekh" but its form from "šin", while the letter San, which occurred in a few dialects only, took its name from "šin" but its place in the alphabet from "ṣādē". A further Greek letter of uncertain origin, sampi, is found occasionally, and may represent an affricate, such as . For the special case of zeta, see Zeta
Sixth Letter (Plato) Sixth Letter (Plato) The Sixth Letter, or Sixth Epistle, is one of thirteen letters which are traditionally attributed to Plato. Unlike the large majority of Plato's major works, the Letters are not Socratic dialogues. Further, despite their traditional attribution to Plato, the Letters are variously held to be spurious or suspect by modern scholarship. Collectively, the thirteen Letters are commonly grouped together as one larger item (called either Letters or Epistles). In turn, this larger collection of Letters is traditionally the last item in the "Thrasyllan tetraologies", a traditional grouping of the major works of Plato which divides them into