Complex sentence: The original version of the inventory included only those three factors, and was published in 1978 as the Neuroticism-Extraversion-Openness Inventory (NEO-I).
Split into simpler sentences: The original version of the inventory, which was published in 1978, included only those three factors. The inventory was then called the Neuroticism-Extraversion-Openness Inventory (NEO-I).