Pope Leo VIII has been listed as both the 131st Pope and the 132nd Pope. He is also listed as both an antipope and an official Pope. It’s all very confusing. This mess was started when his predecessor Pope John XII(who was terrible)started plotting against Holy Roman Emperor Otto I. Otto marched on Rome and ran John out of town,quickly electing Leo to take his place. Leo wasn’t even a priest,he wasn’t anything really but a layman of the Church(he seems to have been picked out of a crowd randomly). In the span of several hours he was ordained every rank in the Church,from a doorman to a lector to a altar boy to deacon and finally moved up to Bishop of Rome. Once Otto left town,sneaky Pope John XII marched some mercenaries back into Rome and took back his Papacy by force,causing Leo to flee to Otto for help. John was sitting pretty smug on the Chair of Peter when he died suddenly(and scandalously).
With Leo nowhere in sight(and not really missed),the Church elected Benedict V as their new Pope….which infuriated Otto who had planned on having his stooge Leo resume his Papal duties. Leo rode back into the city with Otto and had the Papal vestments stripped off of Benedict and had Benedict’s staff smashed over the poor man’s head. On the bright side,Benedict was allowed to slip off to Hamburg and remain a deacon there for the remainder of his life. Since Benedict and Leo overlap each other,depending on which book you’re checking they could be flipflopped in order.