Original: On September 7, 1949 he was elected as the first president of the federal Bundesrat of Germany, acting as head of state until Theodor Heuss was elected five days later.
Simplified: From 7 September 1949 to 6 September 1950 he was the first President of the Bundesrat. This also mean that between 7 and 13 September he was Acting President of Germany, until Theodor Heuss was elected Federal President.