"Dirk VI (c. 1114 – 5 August 1157) was Count of Holland between 1121 and 1157, at first, during his minority, under the regency of his mother Petronilla. He was the son of Count Floris II. After his death he was succeeded by his eldest son Floris III. He married Sofie of Salm, Countess of Rheineck and Bentheim. She was heiress of Bentheim, which she ruled together with her husband and which was inherited by the couple's second son Otto after his parents' death." - (en.wikipedia.org 10.04.2021)