Complex sentence: By 1960 the company was producing off-the-peg suits, and in 1969 Eugen retired to leave the running of the firm to his sons Jochen and Uwe, who began the international development.
Split into simpler sentences: By 1960 the company was producing off-the-peg suits. In 1969, Eugen retired leaving the company to his sons Jochen and Uwe, who began international development.