The Cross of Cornado is a historical artifact that was owned by Cornado.
After slipping out of Cornado's possesionthe Cross was lost for over 300 years. It was discovered in Utah during 1912, and a young Monty Jones tried to take it from the discoverers so it would not go into a private collection but instead into a museum where it belonged. However the law took the finding party's side and took the cross from Monty who had stolen it and gave it back to the owners. Years later Monty reclaimed the Cross from its owner and jumped off his ship escaping with it as the ship explodes. The Cross now presumably resides in a museum.
Unlike most artifacts Monty has quested for, the Cross of Cornado has no special powers it grants the owner, it only has historical value.