The Bibliotheca Thysiana was erected in 1655 to house the book collection of the lawyer Johannes Thysius (1621–1653). Upon his early death, he left a legacy of 20,000 guilders for the building of a public library ("tot publycque dienst der studie") with a custodian's dwelling. Designed by the architect Arent van ‘s-Gravensande, the building follows the Dutch Classical style and is regarded as one of the jewels of Dutch 17th-century architecture. Bibliotheca Thysiana is one of the Top 100 Dutch heritage sites. It is distinguished by its balanced proportions and the purity of its Ionic order on top of a high basement.