When buying Roman swords, consider material, design, and craftsmanship. Opt for high-carbon steel or Damascus steel for durability and sharpness. Choose historically accurate designs like the Gladius, ideal for close combat, or the Spatha, suited for cavalry. Ensure the sword has a full tang construction for strength and balance. The grip should be comfortable, often featuring wood or bone handles for authenticity. Pay attention to blade tempering for resilience.