The Mauritshuis, which housed the library, soon proved too cramped to hold the collection and in 1819 the King decided to move the library and the cabinet of coins and medals to the stately residence on 34 Lange Voorhout. This magnificent mansion, which Adriana Huguetan had commissioned the French architect Daniel Marot to build in 1733, had served as the palace of the King and the Crown Prince at the beginning of the nineteenth century. In this building William I opened the Koninklijke Bibliotheek in 1821, and it was to stay there until 1982. The Koninklijke Bibliotheek continued to grow through purchases and donations. In 1827 the Dutch government purchased for 8,000 guilders the remainder of the library of the Abbey of Tongerlo, which had been dissolved in 1796 under French rule.
Some acquisitions deserve to be mentioned separately.
The two miniatures depicting the presentation of the manuscript to the Abbey of Egmond by Count Dirk II and his wife are the oldest examples of Dutch painting. The year 1835 saw the end of the period of office of the first Librarian, Flament, when he died at the age of 77. He was succeeded by J.W. Holtrop, who focused his attention on the study and bibliographical description of early printed books. Both works were the result of scholarly research, based on the comparison of typeface for the identification and dating of incunabula. They brought him international fame as one of the founders of modern incunabula research.