Bertold IV of Zähringen , born towards 1125, dead the December 8th 1186, was duke of Zaehringen of 1152 with 1186 and count de Boulogne of 1183 with 1186. It was wire of Conrad Ier, duke of Zaehringen and Clemence de Namur.

Shortly after its advent, supported by the emperor Frederic Barberousse, it prepares the conquest of the Comté of Burgundy, but finally Frederic prefers to marry the heiress of the county which escapes Berthold. In compensation, it accepted in 1156 the title of vice-chancellor of Burgundy and the authority on the towns of Geneva and Lausanne, then on Zurich in 1173. In 1157, Berthold had founded the town of Freiburg. By marriage, it also acquires the Comté of Boulogne.

Marriages and children

He married in first weddings Hedwige de Froburg († 1183), and had:

• Bertold V (1160 † 1218), duke of Zaehringen
• Agnes (1160 † 1239), married Egon IV († 1230), count d' Urach
• Anne, married to Ulrich III († 1227) count de Kyburg

It remarie in 1183 Ide of Lorraine († 1216), girl of Mathieu of Alsace and Marie of Blois, count and countess of Boulogne, but did not have children.