 In 1630 he married Maria Overlander van Purmerland, the only surviving child of Volkert Overlander, merchant and one of the founders of the Dutch East Trading Company, and a few times burgemeester of Amsterdam.When his father-in-law died, Banninck Cocq inherited his properties, including a canal house, the castle of Ilpenstein north of Amsterdam along with the title Lord of Purmerland and Ilpendam.Banninck Cocq decorated the main hall with portraits of his wife's ancestors.