Original: He served as deputy chairman of the SPD party of Wuppertal , and was elected later on to the City Council ( 1964-1978 ) , where he served as chairman of the SPD Group ( 1964-1967 ) and later as Mayor ( 1969-1970 ) .
Simplified: He served on the City Council ( 1964-1978 ) , where he was as chairman of the SDP Group ( 1964-1967 ) and later as Mayor ( 1969-1970 ) .