Alessandro di Spina
Alessandro di Spina
The identity of the man who invented reading glasses has long remained a subject of speculation, with opinions divided between Alessandro di Spina and Salvino degli Armati (d. 1317). Little is known about either, and it is likely that both contributed significantly to the development of spectacles; however, a slim majority of scholarly opinion seems to favor Spina.
Magnifying glasses, as well as lenses that used the sun's heat to create combustion, had been known since ancient times. The ancients, however, seem to have been unaware of refraction, or of the relationship between the shape of a lens and its magnifying qualities. Nor do they seem to have applied the concept of magnification to the creation of devices for aiding vision. Only in the eleventh century did Ibn al-Haitham (Alhazen; 965-1039) recognize the correlation between the curved surface of a semi-spherical lens and its powers of magnification.
Later, Robert Grosseteste (c. 1175-1253) became interested in experiments with magnifying lenses, and instilled this interest in his most famous pupil, Roger Bacon (1213-1292). The latter went on to conduct a number of experiments with mirrors and lenses, and suggested in his Opus majus (1268) that lenses properly shaped might have a corrective effect on persons with poor eyesight. Bacon himself did not carry his experiments very far, but it is likely his writing paved the way for the development of spectacles two decades later.
Of the two men who laid claim on the invention of eyeglasses, little is known. Armati developed his lenses in Florence between 1285 and 1299, whereas Spina's have been dated as early as 1282. Scholars are more certain about the location where spectacles made their first appearance: probably in Venice, and certainly in northern Italy. Soon the invention spread to the Netherlands as well.
In some sources, Spina is cited as a friend of Armati, and indeed Armati supporters have maintained that the latter actually made the first pair of glasses for Spina. It is quite possible the two men knew each other, though far from certain. As for Spina's profession, he is commonly cited as a Dominican monk. He died in Pisa in 1313.