At his trial, Valdemar was accused of treason, murder, mental domination and genetic manipulation of the human form. Thanks to testimonies by former allies of his, he was found guilty. He declared he would have his revenge before being killed.
He ended up in 19th century France. There he began capturing young girls with promises of greatness. He had them bring genetic samples to him so as to check the target's ancestry. He hoped to find the ancestors of those who had betrayed him and kill them. However, each sample was checked to confirm they were not relatives of his.
In 1858, the Eleventh Doctor used the vibrations of the Notre Dame's bell to break his hold on the girls. They began encircling him and he fell from the roof to his death. (COMIC: The Screams of Death)