This area consists of two identical rooms which in the seventeenth century served as the bedrooms of the brothers Hendrick and Louys Trip. The architect Justus Vingboons designed an alcove and a portal for both rooms, containing a spiral staircase linking the rooms to the ground floor and the attic.
In the period 1815-1817, when the Trippenhuis was converted to accommodate the Royal Institute of Sciences, Literature and Fine Arts and the Royal Museum, architect Abraham van der Hart (1747-1820) created an opening in the dividing wall by removing the chimney breasts on both sides. The pillars which frame this opening were designed by Vingboons and are taken from the large anterooms. In 1817 these former 'alcova kamers' of the Trip brothers were taken into use as the library of what was then the Royal Institute of Sciences. In 1988 the entire collection was moved to modern premises on Joan Muyskenweg in Amsterdam.