Frans Pouwelszoon van Oosten bought a house on Achterom in 1639. He opened a pottery which took its name from the brewery and malthouse that had previously been housed on the premises. In 1653 Van Oosten sold the property to master potter Jacob Jacobs de Kerton, who bought up several more houses.
In 1675 De Kerton sold the company to Dirk van der Kest. It would pass into the hands of Van der Kest’s daughter-in-law Elisabeth de Vlugt 25 years later. She and her second husband Adam Diderikszoon van Bleiswijck ran De Ham until 1726, when they sold it to Jan Frans Schoonjan and the company was dissolved.
 Hoekstra-Klein, part 13: 117 and 128