Upvote:1
It was for a slow, painful and also humiliation. The cross had no symbolic meaning in a crucifixion, it could have been any wooden construction. Historically crucifixion actually means impaling on a plank, piece of wood ,etc. The word cross actually comes from the word crux
which defers to a wooden construction(or tree) used for impaling people on. Where it came from we don't know, the oldest registered crucifixion is before ancient Rome by the Persians somewhere 500 B.C.