Sampi

Sampi (Ϡ, ϡ) is an old Greek number sign that stands for the number 900. In early Ancient Greek it was sometimes also used as a real letter of the Greek alphabet, but only in the dialect of a few Greek cities in Ionia (for example Miletus) between the 7th century and 5th century BC. At that time sampi looked like Ͳ, and it was probably spoken like "ts" or "tch". Later, people stopped writing it because they no longer spoke the words that way, and they wrote double sigma (ΣΣ) instead. However, people also used Greek letters to write numbers, and here they kept sampi to write the number 900. Over time, the form of sampi was changed from to or and at last to .