Cross,
an instrument of punishment consisting of two pieces of timber placed across each other, in various forms. It was used from the earliest time, especially throughout the Roman Empire, where crucifixion was regarded as the most infamous of deaths. By the death of Christ, the cross, from being an object of horror, became the symbol of the Christian world, and, from respect for this symbol, Constantine abolished the punishment throughout the Roman Empire.
Entry from Everybody's Cyclopedia, 1912.