The 19th Century

Charles Babbage

Charles Babbage, (born December 26, 1791, London, England—died October 18, 1871, London), English mathematician and inventor who is credited with having conceived the first automatic digital computer.
The idea of mechanically calculating mathematical tables first came to Babbage in 1812 or 1813. Later he made a small calculator that could perform certain mathematical computations to eight decimals. Then in 1823 he obtained government support for the design of a projected machine, the Difference Engine, with a 20-decimal capacity. Its construction required the development of mechanical engineering techniques, to which Babbage of necessity devoted himself. In the meantime (1828–39), he served as Lucasian Professor of Mathematics at the University of Cambridge.

During the mid-1830s Babbage developed plans for the Analytical Engine, the forerunner of the modern digital computer. In that device he envisioned the capability of performing any arithmetical operation on the basis of instructions from punched cards, a memory unit in which to store numbers, sequential control, and most of the other basic elements of the present-day computer.
In 1843 Babbage’s friend mathematician Ada Lovelace translated a French paper about the Analytical Engine and, in her own annotations, published how it could perform a sequence of calculations, the first computer program. The Analytical Engine, however, was never completed. Babbage’s design was forgotten until his unpublished notebooks were discovered in 1937. Babbage lived and worked for over 40 years at 1 Dorset Street, Marylebone, where he died, at the age of 79, on 18 October 1871; he was buried in London's Kensal Green Cemetery. According to Horsley, Babbage died "of renal inadequacy, secondary to cystitis.

Ada Lovelace

The daughter of famed poet Lord Byron, Augusta Ada Byron, Countess of Lovelace — better known as "Ada Lovelace" — showed her gift for mathematics at an early age. She translated an article on an invention by Charles Babbage, and added her own comments. Because she introduced many computer concepts, Lovelace is considered the first computer programmer.
Around the age of 17, Ada met Charles Babbage. The pair became friends, and the much older Babbage served as a mentor to Lovelace. Through Babbage, Lovelace began studying advanced mathematics with University of London professor Augustus de Morgan.

Lovelace was later asked to translate an article on Babbage's analytical engine that had been written by Italian engineer Luigi Federico Menabrea for a Swiss journal. She not only translated the original French text into English but also added her own thoughts and ideas on the machine. Her notes ended up being three times longer than the original article. Her work was published in 1843, in an English science journal. Lovelace used only the initials "A.A.L.," for Augusta Ada Lovelace, in the publication.
Lovelace's article attracted little attention when she was alive. In her later years, she tried to develop mathematical schemes for winning at gambling.
Lovelace died at the age of 36 on 27 November 1852, from uterine cancer probably exacerbated by bloodletting by her physicians. The illness lasted several months, in which time Annabella took command over whom Ada saw, and excluded all of her friends and confidants. Under her mother's influence, Ada had a religious transformation and was coaxed into repenting of her previous conduct and making Annabella her executor. She lost contact with her husband after confessing something to him on 30 August which caused him to abandon her bedside. She was buried, at her request, next to her father at the Church of St. Mary Magdalene in Hucknall, Nottinghamshire.