Delft Scientific Hub

When Antoni van Leeuwenhoek makes a name for himself as a researcher the 17th century, Delft is one of the Republic’s larger and more prosperous cities. There is widespread interest in science, which is also reflected in the art of the period: Johannes Vermeer creates paintings with titles including The Astronomer and The Geographer, and father and son team Van Mierevelt paint the Anatomy Lesson of Dr Willem van der Meer.

The Low Countries experience rapid development in the 16th century. Prosperity increases swiftly due to innovations and specialisation in various sectors, such as agriculture and fishing. An entire range of products are exported all over Europe via an extensive trade network. This development is not restricted to cities; the countryside also benefits. Progress is also made in education: in 1560, Antwerp is already home to 150 private schools teaching in Dutch.

It is also a period of major social unrest. The Austrian Netherlands are part of the Spanish Habsburg Empire, in which Protestants are actively prosecuted, and the Spanish war against France brings high taxes. The discontent comes to a head in the mid-16th century, in a revolt against Spain. This revolt is centred in Delft. The leader of the opposition, William I, Prince of Orange, lives in the Prinsenhof in the city – the site of his murder in 1584.

1557-1559: plague epidemic in Delft

The doctor Pieter van Foreest is appointed as city physician. Van Foreest breaks with the established tradition of acting in accordance with historical texts, instead basing his treatments on his own observations. He subsequently records his observations in a series of publications. Approximately 20% of the population die during the plague epidemic.

1586: publication of De Beghinselen der Weeghconst (The Principles of Statics)

In this book, engineer Simon Stevin details an experiment that he conducted together with Jan Cornets de Groot (Major of Delft) from atop the tower of the New Church in Delft. By dropping 2 lead balls of different weights, they demonstrate that heavier and lighter objects fall at the same speed. Aristoteles was wrong.

1596: π up to 32 decimal places

Ludolph Van Ceulen, born in Hildesheim in Germany, moves to Delft in 1562 to teach fencing. He later declares himself a first-class arithmetician. His book Van den Cirkel (Of the Circle) is published in 1596, in which he accurately determines the numerical value of the mathematical constant π to 32 decimal places – a world record at the time. The book brings him (international) fame.

1600: School for Dutch Mathematics

In 1600, Stevin, De Groot and Van Ceulen are involved with founding the School for Dutch Mathematics, an engineering school in Leiden. The war against Spain means that engineers capable of building defences are in great demand. Stevin devises the curriculum, De Groot becomes the Director and Van Ceulen teaches mathematics.

1608: invention of the telescope

Following the invention of the telescope in the Republic, telescopes are made in Delft as early as 1609. These are probably made by Evert Harmanz Steenwijk, a lens grinder working in Delft. In approximately 1650, Johan van der Wyck, a military engineer in Delft, makes a name for himself as an internationally acclaimed telescope and microscope maker.

1614: Anatomy Theatre

There is fervent interest in the medical sciences in Delft. As early as 1614, the city established an anatomy theatre, where new medical techniques are demonstrated and experiments are conducted. This was also the home of the Surgeon’s Guild. Several ‘cabinets of natural curiosities’ could also be found in Delft; these were highly renowned and attracted both Dutch and international scholars.

1633: Jacob Spoors

In 1633, Jacob Spoors, a surveyor in Delft, investigated the extent to which he is able to observe a candle flame at night, as an analogy for a star. Due to the fact that the light from a star travels through a vacuum, he concluded that stars had to be smaller than initially presumed. He publishes his findings in 1638. Antonie van Leeuwenhoek worked with Spoors for a period of time as an assistant surveyor. Spoors was also closely acquainted with telescope and microscope makers Evert Harmanz Steenwijk and Johan van der Wyck.

1666: Reinier de Graaf

When Reinier de Graaf moves to Delft as a physician in 1666, he is already an internationally renowned medical researcher. He has conducted pioneering research into the structure and function of male and female genitals. De Graaf introduces Antonie van Leeuwenhoek to the Royal Society in London as a correspondent member.