The center of the Nieuwmarkt was built in 1488 and functioned as the city gate of Medieval Amsterdam. The weigh house was then called the Sint Antoniespoort. Over time, Amsterdam had grown in size and the weigh house was no longer the outside of the city. When the weighing house on Dam square had become too small, the Sint Antoniespoort was given a new function from 1617: the city gate was converted into a weighing house. Above the doors, roofs were made under which scales were placed, on which besides goods for daily use also anchors and artillery of the nearby shipyards were weighed.
Some guilds were housed on the top floor of the weigh house. Until 1869, the Surgeons' Guild used the top floor, the Theatrum Anatomicum, as a lecture hall. Here, corpses of criminals were dissected during anatomy classes in winter. In 1632 Rembrandt painted here ‘De anatomische les van dr. Nicolaes Tulp’ (The anatomy lesson of Dr. Nicolaes Tulp). Nowadays Restaurant-Café In de Waag is located in this historic building on the Nieuwmarkt. The beautiful terrace and historic interior make it a perfect place for a drink, lunch or dinner.