iride (On the Rainbow), written between 1220 and 1235, mentions using optics to "read the smallest letters at incredible distances". A few years later in 1262, Roger Bacon is also known to have written on the magnifying properties of lenses. The development of the first eyeglasses took place in northern Italy in the second half of the 13th century. Independently of the development of optical lenses, some cultures developed "sunglasses" for eye protection, without any corrective properties. For example, flat panes of smoky quartz were used in 12th-century China, and the Inuit have used snow goggles for eye protection. Invention The earliest recorded comment on the use of lenses for optical purposes was made in 1268 by Roger Bacon. The first eyeglasses were estimated to have been made in Central Italy, most likely in Pisa, by about 1290: In a sermon delivered on 23 February 1306, the Dominican friar Giordano da Pisa (–1311) wrote "It is not yet twenty years since there was found the art of making eyeglasses, which make for good vision ... And it is so short a time that this new art, never before extant, was discovered. ... I saw the one who first discovered and practiced it, and I talked to him." Giordano's colleague Friar Alessandro della Spina of Pisa (d. 1313) was soon making eyeglasses. The Ancient Chronicle of the Dominican Monastery of St. Catherine in Pisa records: "Eyeglasses, having first been made by someone else, who was unwilling to share them, he [Spina] made them and shared them with everyone with a cheerful and willing heart." Venice quickly became an important center of manufacture, especially due to using the high-quality glass made at Murano. By 1301, there were guild regulations in Venice governing the sale of eyeglasses. and a separate guild of Venetian spectacle makers was formed in 1320. In the fourteenth century they were very common objects: Francesco Petrarca says in one of his letters that, until he was 60, he didn't need glasses, and Franco Sacchetti mentions them often in his Trecentonovelle. The earliest pictorial evidence for the use of eyeglasses is Tommaso da Modena's 1352 portrait of the cardinal Hugh de Provence reading in a scriptorium. Another early example would be a depiction of eyeglasses found north of the Alps in an altarpiece of the church of Bad Wildungen, Germany, in 1403. These early glasses had convex lenses that could