However, his brothers questioned the legitimacy of his sole rule and demanded a share of his inheritance.
They asked the grandfather Theodoric III, Count of Montbéliard [fr; nl] to arbitrate the dispute.
Theodoric deviated from the usual practice in those days, and decided that the county should be regarded as an indivisible entity.
He awarded the county to Amadeus, but acknowledged that his brothers were entitled to a share.
Amadeus was married to Jordanna, the daughter of Count Ulrich of Arberg.