His contemporaries described him as a handsome, stocky man, blond and fair-skinned, an adventuresome and high-spirited person, with an inquisitive and active mind.
It is more common in fair-skinned people and it is associated with those who are frequently exposed to the sun, as it is usually accompanied by solar damage.
For example, sunlight exposure has a much stronger influence on skin cancer risk in fair-skinned humans than in individuals with an inherited tendency to darker skin.