Louise Rasmussen

Louise Christine Rasmussen, also known as Countess Danner , was a Danish Ballet dancer and stage actor. She was the mistress and later the morganatic spouse of King Frederick VII of Denmark. She was not a queen consort, but officially styled Countess Danner.

She got to know Crown Prince Frederick through Berling in the 1830s and had a relationship with him during the 1840s. Frederick became king in 1848. He wanted to marry Louise, but the government forbade it, as Frederick was childless and no children born from a marriage with Louise would have been entitled to the throne. The reformed law of 1849, however, made the king so popular that he was able to have his wish granted.

Source: Wikipedia