This is believed to be the only release of Ultima I by Sierra. In 1981-1982 Sierra was given the rights by Richard Garriott to publish Ultima II - Revenge of the Enchantress under its "SierraVenture" label. The following year Sierra ported Garriott's original Ultima to the Atari 8-bit platform which is what you see here. Interestingly enough, the artwork on the front of Ultima I is actually the artwork from the back of Ultima II. The rest of the Ultimas (except Mt. Drash) were published by Origin Systems Inc.