The growth of the National Museum of Antiquities would prove to be depended much more upon foreign investments. Despite the gathering of antiquities from various Dutch organizations, the really important additions to the museum would come from buying personal collections. Among the first of these was the first Rottiers Collection. It belonged to a retired Flemish colonel who had begun collecting during a stay in Athens. In 1820, this collection was offered to the government of the Low Countries and Reuvens was sent to determine its value and recommend on whether to buy or not. Reuvens was enthusiastic about the collection because it contained original Greek sculpture and Greek pottery, categories which lacked in the Leiden collection until then. Cautioning the ministry not to buy at any price, the Rottiers collection was eventually sold for the sum of 12,000 guilders and placed in the National Museum of Antiquities.