Well, yes: Charles Darwin was born on February 12, 1809, thereby giving the answer to the Marxist riddle (Groucho's, not Karl's) "Who was born on Lincoln's birthday?" In 1798—200 hundred years ago—Darwin existed only as the intellectual gleam in his grandfather Erasmus's eye.
The year 1859 is often referred to as the "Darwinian Moment" when our worldview began to change simultaneously in a number of areas. Jacques Barzun developed his popular Darwin, Marx and Wagner (1941) around the fact that in the single year 1859 Darwin published On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, Marx wrote Principles of Political Economy, and Wagner wrote his opera Tristan and Isolde. Michael Ruse has emphasized that 1859 was also the year that a group of English clergy wrote Essays and Reviews, a liberal (that is, enlightened) view of the evidence for miracles, which distracted a good deal of public attention away from Darwin.
My physicist friend Gino Segré points out that in 1859 Leverrier discovered in the precession of the perihelion of Mercury, the only known exception to Newtonian theory, later explained by Einstein's general theory of relativity. That year, too, Kirchov made the crucial observations on black body radiation that were only later fully explained by Planck's quantum hypothesis.
We could add that 1859 was the year that Dickens published A Tale of Two Cities and John Stuart Mill wrote On Liberty. Also, Fitzgerald translated The Rubaiyat of Omar Khayyam, and Trollope wrote The Bertrams. All of which allows one to ask: So what? A case can be made for the importance of almost any year (except perhaps for 1845 and 1849, which seem to have been particularly barren in the literary department, at least).
Why then 1798? Because if we were to claim that a particular year framed the genesis of The Origin, it would be 1798 (or, more generously, the period 1796 to 1798). Erasmus Darwin completed publication of Zoonomia or, the Laws of Organic Life in 1796. 1797 saw the birth of Charles Lyell, the great English geologist, and the death of William Hutton, as great a Scottish one. Above all, in 1798 came the anonymous publication of Thomas Robert Malthus's first version of An Essay on the Principle of Population, as It Affects the Future Improvement of Society, with Some Remarks on the Speculations of Mr. Godwin, M. Condorcet, and other Writers.
Malthus attempted to make a science of "the nature and causes of poverty, as Adam Smith had enquired into the nature and causes of wealth." In the process, he became "the best-abused man of his age" and "Malthusian" has become, like its sister term "Darwinian," an epithet for those necessities that constantly challenge the best hopes of the human spirit.
Thomas Robert Malthus (1766–1834) graduated from Cambridge in 1788 and became a parson the next year. In 1805 he started teaching history and political economy at the college of the East India Company, a post he held until his death. His immediate stimulus for writing the Essay was in part reactive, in part creative. In 1796 (note the date) William Godwin, a clergyman, social philosopher and journalist, had written The Enquirer, a popular book (in the sense both of non-technical and broadly read) summarizing a whole school of progressive thought owing much to the French philosopher Condorcet (for example, his Esquise d'un Tableau Historique des Progrès de l'Esprit Humain 1794). In The Enquirer Godwin promotes the idea of the perfectibility of man and society and of an equality among men driven by the economics of growth. Having proceeded upward from the savage, man will continue toward perfection as a law of nature. In Godwin's utopian economics, population growth means a growth in labor, growth is only good, and can only lead to greater wealth and improvement for all—provided, of course, that institutions (that is, the "established order") change appropriately.