This house was built in 1617 for the wealthy Willem van den Heuvel. He named himself Guillelmo Bartolotti, after an Italian uncle from whom he had inherited a lot of money. There are two cartouches with on the left the painted inscription "Ingenio et Assiduo Labore" (by ingenuity and diligent diligence) and on the right "Religione et Probitate" (by religion and righteousness). The red brick facade decorated with mountain stone is the work of city architect Hendrick de Keyser. Number 172 is currently used as an office of the Vereniging Hendrick de Keyser.
Bartolotti House came into possession of the association in two parts: in 1924 and 1971. From 1971 the offices and library of the Theater Museum were located there and the annex of number 170 was occupied by Gustav Leonhardt, harpsichordist and musicologist. The building contained many passages with the adjacent buildings. In 2009, these passages were removed and the old structure of the house was restored. After a major restoration in 2016, the building has been furnished as a Museum house and the building is rented out for (special) events. Photo 1 and 2 by Arjan Bronckhorst.