John Ruskin is certainly not a household name these days. But at least one historian contends that he may have been the single most influential person of the past 200 years.

A brilliant philomath, Ruskin published over 250 books over the course of his extraordinary life, on a wide variety of subjects. Perhaps best known in his time as an art critic, he championed the works of J.M.W. Turner and Tintoretto and was largely responsible for elevating them to prominence. Ruskin’s work on literature influenced and was admired by a wide range of writers, including T.S. Eliot, Ezra Pound, Oscar Wilde, Charlotte Bronte, and Leo Tolstoy (who called Ruskin “one of the most remarkable men of all time”). Ruskin was also hugely influential among architects, and among those who acknowledged being indebted to him were Frank Lloyd Wright and the French urban planner Le Corbusier. Ruskin’s scientific and naturalist writings made him one of the earliest environmentalists. Mahatma Gandhi said that after reading a book by Ruskin on social theory, he was transformed “overnight from a lawyer and city-dweller into a rustic.” The list of people who acknowledged being influenced by the work of John Ruskin looks like a Who’s Who of artists and intellectuals of the 19th and 20th centuries.

But being a genius making a profound impact on the course of history did not assure Ruskin a happy life. He suffered from bouts of severe mental illness and depression at times and his marriage to the beautiful young Effie Gray was annulled eight years later, unconsummated, for reasons that are still unknown (but the subject of much speculation).

Born in London in February 1819, John Ruskin died in Lancashire England on January 20, 1900, one hundred twenty-three years ago today.

The painting is a portrait of Ruskin by the British painter Sir John Everett Millais. Millais began the portrait while on vacation with John and Effie Ruskin in Scotland in 1853, believing that his work would “make a revolution in landscape painting.” While working on it, Millais fell in love with the beautiful but neglected Mrs. Ruskin. Shortly after the Ruskin’s’ marriage was annulled in 1855, Millais and Effie married, and they went on to have eight children together. Millais described finishing the portrait of Ruskin, which now hangs in the Ashmolean Museum at Oxford, as “the most hateful task I have ever had to perform.”