Map of Old Town of Klaipėda
The Teutonic Knights built a castle in the *Pilsāts Land of the Curonians and named it Memelburg; later the name was shortened to Memel. From 1252 to 1923 and from 1939 to 1945, the town and city were officially named Memel. Between 1923 and 1939, both names were in official use; since 1945 the Lithuanian name of Klaipėda has been used.
The names Memelburg and Memel are found in most written sources from the 13th century onwards, while Klaipėda is found in Lithuania-related sources since the 15th century. The first time the city was mentioned as Caloypede in the letter of Vytautas in 1413, for the second time in the negotiation documents of 1420 as Klawppeda, and for the third time in the Treaty of Melno of 1422 as Cleupeda. According to Samogitian folk etymology, the name Klaipėda refers to the boggy terrain of the town (klaidyti=obstruct and pėda=foot). Most likely the name is of Curonian origin and means "even ground": "klais/klait" (flat, open, free) and "ped" (sole of the foot, ground).
The lower reaches of the Neman River were named either *Mēmele or *Mēmela by Scalovians and local Curonian inhabitants. In the Latvian Curonian language it means mute, silent (memelis, mimelis, mēms). This name was adopted by speakers of German and also chosen for the new city founded further away at the lagoon.