Roland Matthes
Roland Matthes (German pronunciation: [ˈʁoːlant ˈmatəs], audio ; 17 November 1950 – 20 December 2019) was a German swimmer and the most successful backstroke swimmer of all time. Between April 1967 and August 1974 he won all backstroke competitions he entered. He won four European championships and three world championships in a row, and swam 19 world and 28 European records in various backstroke, butterfly and medley events. He was trained by Marlies Grohe.
Source: Wikipedia