"Both before and during the Second World War the German companies AES and Atlas worked on torpedo technology including the seeker used in the T5 Zaunkonig I (Wren I) homing torpedo (which entered service in September 1943) and the T11 Zaunkonig 2 with ECCM capability.

With the creation of the post-war West German Navy (Bundesmarine) national interest in torpedoes for both submarines and FACs was revived, although the first submarines had the US Mark 37 while the FACs were armed with either the wartime German Type G7a or the British Mark 8 weapons. The Bundesmarines' prime interest was in long-range, wakeless, wire-guided homing torpedoes and in view of the fact that the Baltic was the Bundesmarines' main operational area, specific shallow water capabilities were required. Early in 1958 AEG Telefunken (now STN Atlas) began a joint concept study with the Bundesmarine into heavyweight torpedoes. After considering a multirole weapon it was decided to develop dedicated anti-submarine and anti-surface vessel weapons with the two designs having as much commonality as possible.

The ASW weapon had priority and development began in 1960 as DM1 (Deutsches Modell 1) Seeschlange (Sea Serpent) and after extensive trials and testing became operational in the 1970s, then being improved in the mid-1970s as DM1 Mod. Development of the anti-surface vessel weapon was begun by AEG in 1962 as DM2 Seal (although the English spelling is the official one, it is pronounced in German Seeaal or Sea Eel) and it became operational in 1970."