I'm not sure if this the same ten Cate, but in my book "De bekende landheer van Tjampea, c.a., Willem Vincent Helvetius van Riemsdijk"there are a lot of ten Cate family members mentioned and go back quite a ways (to the 1600s in the Dutch East Indies). There is an Ernst ten Cate mentioned, born in Rampah on Sep 6 1909.If this is the same one you asked about, his parents were William ten Cate born Buitenzorg, 1 nov 1881, married 13 Jan 1906 to Johanna Wilhelmina Hendriks-Tewoe, born in Laboean Deli on 28 March 1886, daughter of Theodorus Hendriks Tewoe and the Javanese woman Sarinah. I have much more info about this line of the Ten Cate family in my book. So if you think this is your family, I can send you more information. We may be related through Willem Vincent Helvetius van Riemsdijk who is my GGGG Grandfather.