Sigma Draconis III

From Memory Alpha, the free Star Trek reference

Sigma Draconis III is the third planet in the Sigma Draconis system. It is a moonless M-class planet, larger and more heavily populated than Sigma Draconis IV. By 2268, the planet's inhabitants had a pre-spaceflight culture with an Industrial Scale rating of B, which was equivalent to Earth in 1485, and a technological rating of 3. (TOS: "Spock's Brain")