Two large South American palaeontological vertebrate collections are housed in the Natural History Museum of Denmark, the V. Lausen Collection and the P.W. Lund Collection. Both were collected in the 19th century. During the last ten years these two collections have been reviewed, reassessed and digitalized. New information has been gathered from museum archives, letters, interviews and newspapers. Fossil material has been identified through morphological analysis. The research into the V. Lausen Collection in particular yielded much that was virtually unknown to the public before. Today the collections are kept in a storage facility and are very rarely accessed or studied.