Complex sentence: The pre- 1952 portion of this biography incorporates information derived from the German Wikipedia article His half-sister Heidi, born in 1941, gave him the nickname "Hotte", which he kept for the rest of his life.
Split into simpler sentences: The pre- 1952 portion of this biography incorporates information derived from the German Wikipedia article In 1941 his half-sister Heidi was born. She gave him the nickname "Hotte", which he kept for the rest of his life.