This arrangement was not accepted by all of the nobles at first as she faced opposition from Hendrik van Leuven of Gaasbeek, who was a cousin of her husband.

Adelaide's eldest son, Henry, had physical and mental disabilities which rendered him incapable of effectively ruling the duchy upon his majority.

It has been argued by historians such as H. Pirenne and B. Blumenkranz that Thomas Aquinas addressed his Epistola ad ducissam Brabantiae to Adelaide after she wrote to him, asking for counsel in regards to her Jewish subjects.

The work was only a minor treatise of Aquinas's; however, it has proven significant with historians of antisemitism and taxation during the Medieval era, the two areas of concern.

Historians such as Raymond van Uytven doubt that the similarities between the two documents are a coincidence, implying that Adelaide related her late husband's concerns to the theologian.