The previously known ties were reported to the Latvian community in the Hague by Rundāle palace director Imants Lancmanis.
"Duke Jacob's daughter Maria Amalia was married to Charles I, Landgrave of Hesse-Kassel, and their son became king of Sweden in 1720.
Afterwards the line is completely straight and the current King of Netherlands has sprung from Maria Amalia, the daughter of duke Jacob, in the tenth generation," Imants Lancmanis told Latvian Television.
While the Netherlands Embassy in cooperation with the Rundāle palace, a major baroque palace built for the Dukes of Courland, has started a project aiming to inform people about the times of long ago.
Duke Jacob Kettler in the 17th century built 70 manufactures, iron kilns, and oversaw the construction of ships for the Dutch navy at the Ventspils port city.
"Duke Jacob studied in Amsterdam and in Leiden. He saw the Netherlands as an example of how you can build a mighty economy and manufacture in a small country," Lancmanis explained.
Lancmanis said that there's not much left from all the things built under duke Jacob. That is, with the exception of his ancestry still living on in the Netherlands' royal family.