Ernest had suffered from a venereal disease in his late teens and early twenties, most likely as the consequence of living a wild, promiscuous lifestyle. He had come to behave in such a fashion by the tutelage of his father, who took his sons to "sample the pleasures" of Paris and Berlin, to Albert's "horror and shame". Ernest had been so visibly deteriorating in appearance as a result that Sarah Lyttelton, a lady-in-waiting of Queen Victoria, observed at Windsor Castle in 1839 that he was "very thin and hollow-cheeked and pale, and no likeness to his brother, nor much beauty. But he has fine dark eyes and black hair, and light figure, and a great look of spirit and eagerness". Later that year, Albert counseled his brother against finding a wife until his 'condition' was fully recovered. He further warned that continued promiscuity could leave Ernest incapable of fathering children. Some historians believe that while he himself was able to father other children, the disease rendered his young wife infertile.