His eldest daughter, Marie, now the widow of Emperor Otto IV, had recently married in July 1220 as her second husband William (I), Count of Holland. Another daughter, Margaret, was the wife of Gerhard (III), Count of Guelders. Her sister, Adelaide, was the widow of Arnoul (III), Count of Loos and Graf of Rieneck, and another sister, Mathilde, the wife of Floris, the son and heir of Count William (I), of Holland by William’s first wife, Adelaide of Guelders: Smets,
Henri I, duc de Brabant
, p. 165;
Genealogia Ducum Brabantiæ Heredum Franciæ
, p. 390 (ch. 7);
Oude Kronik van Brabant
(1855), Codex Diplomaticus Neerlandicus, Utrecht, Second Series, deerde deel, part i, p. 62.