Arnold of Altena, count of Altena, count of Isenberg and Hövel, Vogt of Werden (1166–1209) was a son of Eberhard IV of Berg. He inherited the north-western territorium of Altena, and became 1st count of Isenberg in 1200.
He married Mathilde countess of Cleve daughter of Dietrich III, Count of Cleves and Adelaide of Sulzbach (+12.2.1189). Mathilde's brother was count Diederick IV of Cleve (+1193) who married in 1182 Mechteld (Margaret) of Holland (died after 1203).
Count Arnold of Altena – Isenberg and Mathilde countess of Cleve had issue:
Eberhard II count of Altena and Isenberg (born 1180, died 1209)
Dietrich of Altena, (born before 1180, died on the way back from Rome to Limburg 18 July 1226);
Engelbert of Altena, (1224-deposed 1226 following his implication in Engelbert II of Berg's assassination, rehabilitated 1238-1250) (born before 1200, died 1250);
Philipp of Altena, Propst zu Soest and Domthesaurar in Cologne (born before 1200, died 1264);
Bruno of Altena, (1250–1258) (born before 1200, died 20 December 1258);
Gottfried of Altena, Propst zu St. Martin and Domdechant in Münster (born before 1220, died after 1247);
Adolf von Holte (born 1220, died before 25 January 1260), married to Elisabeth von Holte (died after 1260). They had issue:
Heinrich von Holte, a prior in Cologne (fl. 1261/89);