A contemporary court poem described his appearance at his coronation;
"tall but well proportioned, broad-shouldered with a long and elegant neck, pale and freckled skin, bright and wide blue eyes, and a thick mop of the reddish-gold hair"Mary of York was the sister of Elizabeth of York and daughter of Edward IV and Elizabeth Woodville. We know of her hair colour via some rather strange mechanisms. Mary died in 1482, however, in 1789, workmen carrying out repairs in St. George's Chapel, Windsor accidentally broke into the vault of Edward IV and Elizabeth Woodville. In a small adjoining vault they discovered the coffins of two unidentified children. Strangely they were put back without being examined and the tomb was sealed and inscribed with the names of Mary and her brother George, who died aged 2 (Mary died in her teens). Then in 1810-1813 the tomb was re-opened (but again no real in depth investigation took place). This time the coffin of Mary was opened though. I'll let Wikipedia tell the rest;
The coffin of Mary was opened, the beautiful girl of fifteen who had died a year before her father; a shock of her pale gold hair had insinuated itself through the chinks of the coffin; the eyes were pale blue and open, but turned to dust however soon after the admission of air.It's slightly reminiscent of the supposed opening of Elizabeth Siddal's coffin later that century. Apparently, when her husband Dante Gabriel Rossetti opened it, the coffin was filled with her flowing coppery-red hair.