Determining the "best" sword in history is subjective and depends on various factors, including the specific criteria, cultural context, and personal preferences. Many exceptional swords have been crafted throughout history, each with its unique characteristics and advantages. Here are a few notable swords that are often regarded as among the best:

1. Japanese Katana: The katana, a traditional Japanese sword, is renowned for its craftsmanship, sharpness, and balance. It has become iconic for its elegant design, versatility in combat, and historical significance within samurai culture.
2. European Longsword: The European longsword, commonly associated with medieval knights, was a versatile weapon known for its effectiveness in both cutting and thrusting. Longswords were crafted with quality materials and demonstrated excellent balance and durability.
3. Viking Ulfberht Sword: The Ulfberht sword is a type of Viking sword known for its exceptional quality and advanced craftsmanship. These swords were characterized by their high carbon steel blades, superior strength, and distinctive inscription reading "Ulfberht."
4. Indian Tulwar: The tulwar, a curved sword from India, is recognized for its elegant design, balance, and effectiveness in combat. Tulwars were crafted with high-quality steel and were renowned for their cutting ability and maneuverability.
5. Persian Scimitar: The Persian scimitar, with its curved blade, is recognized for its cutting power and fluid slashing motions. Scimitars were used by various cultures throughout the Middle East and had a significant impact on historical warfare.

It is important to note that the "best" sword can be subjective and depends on individual preferences, combat style, historical context, and the specific criteria being considered. Each sword has its own merits, cultural significance, and intended use. The choice of the "best" sword ultimately depends on personal opinions and the specific requirements of the user.