The author of this German version SARGON 2 in unknown. It is however the famous SARGON 2 chess program written by Dan & Kathe Spracklen which was originally published in 1983 for the Commodore 64. One nice feature in this version are the chess clocks showing on the same screen as the chess board. The engine however is identical to the original SARGON II.
You can read about the original SARGON 2 here:
The approximate rating for SARGON 2 is 1150 - 1250 ELO (1350 - 1450 USCF)