As nearly as historians can pin it down, the engagement ring began as a betrothal or "truth" ring in ancient Rome. The convention of wearing it on the third finger of the left hand also began in Rome, whose congress with Egypt convinced them that the vein of that particular finger led directly to the heart. The Romans were also the first to begin inscribing and engraving their rings, especially engagement rings. Diamonds were in use even in those early days, prized for their supernatural abilities to protect its wearer from poison, insanity and fears.