Complex sentence: He accepted and On 20 November 1945, he played his first post-war concert in Diligentia and a month later, On the occasion of the "Chanoekafeest", he played in Museum Boijmans Van Beuningen in Rotterdam.
Split into simpler sentences: He accepted and on 20 November 1945 he played his first post-war concert in Diligentia. A month later, On the occasion of the "Chanoekafeest", he played in Museum Boijmans Van Beuningen in Rotterdam.