A Latin cross or crux immissa is a type of cross in which the vertical beam sticks above the crossbeam,[1] with the three upper arms either equally long or with the vertical topmost arm shorter than the two horizontal arms, and always with a much longer bottom arm.[2]
If displayed upside down it is called St. Peter's Cross, because he was executed on this type of cross.[3] When displayed sideways it is called St. Philip's cross for the same reason.[3]
Many medieval churches are designed using the Latin cross plan. When looked at from above, it takes the shape of a Latin cross. A Latin cross plan primarily contains a nave, transept, apse, and narthex.