The symbol is derived from Latin C, a rounding of the Greek gamma, which was derived from a Phoenician symbol called gimel or camel, which was in turn developed from an Egyptian symbol.
Latin c had both a g and a k sound. In Anglo-Saxon, c had at first only the k sound, the modern word child having been spelled cild.
By the 12th century c had the sound of s in a number of words.
From this arose the modern rule that c has the s or sh sound before e, i, y ae, and oe, and the k sound in all other cases.
