Short answers, pulled from the story.
Leon Battista Alberti was an Italian Renaissance humanist author, artist, architect, poet, priest, linguist, philosopher, and cryptographer who lived from 1404 to 1472. He epitomised the figure now called a polymath and is considered the founder of European cryptography, a claim he shares with Johannes Trithemius.
Leon Battista Alberti designed the façade of the Rucellai Palace in Florence beginning in 1446, the Tempio Malatestiano in Rimini, and the upper façade of Santa Maria Novella in Florence. His most significant work is the Basilica of Sant'Andrea in Mantua, begun in 1471 and completed after his death, along with San Sebastiano in Mantua.
Leon Battista Alberti wrote Della pittura, also known as De Pictura, which he began in 1435 and which contained the first scientific study of perspective. In it he developed the concept of the Albertian Window, a foundational idea in linear perspective still used today in fields from architecture to computer graphics.
Cryptography historian David Kahn called Leon Battista Alberti the Father of Western Cryptography. Kahn credited him with the earliest Western exposition of cryptanalysis, the invention of polyalphabetic substitution, and the invention of enciphered code. Alberti invented the first polyalphabetic cipher, now known as the Alberti cipher, and the Cipher Disk.
Leon Battista Alberti died in Rome on the 25th of April 1472, at the age of 68. He had taken holy orders, never married, and held the appointment of canon in the metropolitan church of Florence.
Leon Battista Alberti completed De re aedificatoria in 1452, the first architectural treatise of the Renaissance. It was based on the work of Vitruvius and ancient Roman buildings, was dedicated to Pope Nicholas V, and was not published until 1485, after which it became a major reference for architects.