Kings of France
King Henri III
Towards the End of King Henri III's Life
These portraits are from 1580, at about 30 years of age. Yet, note how similar these portraits are to those supposedly from around 1578, where he wears his classic black dress.
His features are much older here, though his apparel is nearly unchanged from the famous black dress.
I can only conclude that some of the King's portraits have never been accurately dated.
RMN Dumonstier Etienne (1574-1603) (attribué à)
Hair & Wigs
The king's hair is brushed away from his face, en ratepenade, and he is often criticized for this style which requires a curling iron. However, his brother King Charles IX wore his hair this way too but Henri's style of wearing the hat set back on his head made the effect more visible while Charles wore his hat cocked to one side, swooped down at the front.
Etienne Pasquier in his Lettres Historiques states that the king wore a hairpiece on a trip to visit Parlement, probably later in life. But wiags were common at the time : the upper classes cut their hair short. This eliminated lice and breeding grounds for problems like ringworm . But, also hair was routinely shaven when a person fell ill: this was done at least until about 100 years ago: Czar Nicolas' II Of Russia children fell sick with measles ca 1910, and there are extent photographs of them without hair
http://www.pollencards.com/art/286309/The_Children_of_Tzar_Nicholas_II_with_Heads_Shaven
Going back to wigs, they were all the rage in the 16th century, and quite elaborate like that on the king's sister Marguerite de France