The alphabet used by the Romans changed over time and for a while "C" was used for both /k/ (as in Kilometre) and /g/ (as in Golf)/.
Spurius Carvilius Ruga, a freed slave who ran a private elementary school in the late 3rd century BCE, is credited with introducing (or perhaps just promoting) the use of a small horizontal stroke to distinguish between the two sounds, so now /g/ would be spelt with a G and /k/ with a C as before. Perhaps he was influenced by his last name being mispronounced as Ruca with a /k/.
This is only a story of course but if true Sp. Carvilius Ruga would have the distinction of making a small but important typographical change that has survived unaltered for more than 2,000 years. Without it we couldn't tell our goats from our coats, our gold from our cold, or our glasses from our classes.