Complex sentence: According to a legend, the town initially was known as "Tusk", however, after a flood that destroyed half of the city it was renamed to Pułtusk ("Pół- " or"puł -" being a Polish prefix for a half).
Split into simpler sentences: According to a legend, the town initially was known as "Tusk". After a flood destroyed half of the city it was renamed to "Pułtusk" ("Pół- " or"puł -" being a Polish prefix for a half).