Koert Sigmund
Kurt Albert was born on July 9, 1933, in Frankfurt am Main, in the same Bürgerhospital where his sister Lotte was born 4 years earlier. The name Kurt was changed in the Netherlands to Kurtie and later Koert.

To date, no photos of either Lotte or Koert Sigmund have been found. The only thing that remains of Kurt Albert is his handwritten name on two notebooks, here spelled as Koert. Additionally, he wrote his name under the verse he wrote in the Poesie album for his sister Lotte. In that Poesie album, there is also a postcard written by him to his older sister, lieffu lot. One of the parents wrote the name Kurti on this card. Apparently, he was called Koertie/Kurti in everyday conversation.