Adriaan Anthonisz

As a mathematician Anthonisz calculated in 1585 the ratio of a circle's circumference to its diameter, which would later be called pi.

[4] Adriaan fathered two sons, and named them both Metius (from the Dutch word meten, meaning 'measuring', 'measurer', or surveyor).

[6] In 1585 Anthonisz discovered that the ratio of a circle's circumference to its diameter, later called pi, approximated the fractional value of ⁠355/113⁠.

[7][8] He is regarded as one of the first military engineers to apply the principles of the Dutch fortification system.

[9] Some of his professional accomplishments included mapping the Berger lake and expanding and fortifying Naarden and Muiden.