After the Polish Piast dynasty united many West Slavic tribes, the ethnonym Liakhy was used to refer to all those tribes and subsequently to the newly established Polish people. It was mainly an exonym — rarely used by Poles themselves in historic times, with the exception of the Lachy Sadeckie — though one of the Old Czech Chronicles states that a legendary person named Lech was the founder of Poland (see Lech, Čech, and Rus). According to Šafárik, the word "Liakh" has its origin in a generic name, "Lech", deriving from a Slavic word for furrow, trough, or field.