 By the end of the 15th century, the bankers and merchants of Florence, Genoa, Venice and Lübeck used this system widely.However, the double-entry accounting method was said to be developed independently earlier in Korea during the Goryeo dynasty (918–1392) when Kaesong was a center of trade and industry at that time.The "Four-element bookkeeping system" was said to originate in the 11th or 12th century.