I would like to end this Quixotic month with a portrait of the creator of this phenomenon, but recently (since 1950) none of the available portraits are considered authentic. 

This is the portrait attributed to Juan de Jáuregui.

Juan de Jáuregui
1583- 1641)
 

Juan Martínez de Jáuregui y Aguilar was a Spanish poet, scholar and painter in the Siglo de Oro.

https://en.wikipedia.org/wiki/Juan_de_Jáuregui

(Possibly) Cervantes. Attributed to Juan de Jáuregui
Circa 1600
Oil on panel
60 x 49.4 cm
Royal Academy of History, Madrid, Spain

 

Portrait of Miguel de Cervantes Saavedra commonly said to be that which, according to the prologue to Cervantes' "Exemplary Novels", was painted by Juan de Jáuregui. Modern scholarship does not accept this, or any other graphic representation of Cervantes, to be authentic, nor is there any documentation for Jáuregui having painted this portrait.