One of Nast's most passionate causes, freeing the slaves, was the subject of many of his wartime illustrations - most notably "Emancipation," a two-page woodcut engraving that appeared in Harper's January 24, 1863, issue in the wake of Lincoln's January 1 Emancipation Proclamation (above).

, "I didn't get into the profession because of Thomas Nast, but the profession is here because of Thomas Nast."

In 1868 Nast started his cartoon campaign against Boss Tweed and his corrupt Tammany Hall political machine, which had been bilking New York City of tens of millions of dollars since 1865.The first salvo was "A Respectable Screen Covers a Multitude of Thieves," a small cartoon that appeared on the back page of the October 10 Harper's Weekly. It showed New York Mayor John T. Hoffman with a self-satisfied look on his face, standing in front of a screen. Behind the screen, a group of men grab fistfuls of money from a box Nast labeled "City Treasury." A sign hanging over their heads reads, "Thou shall steal as much as thou canst. The Ring."

When Ulysses S. Grant was asked to name the one American civilian who had the most impact on the course ofthe Civil War, he replied: "I think, Thomas Nast. He did as much as any one to preservé the Union and bring the war to an end."

On September 23rd, 1871, Nast drew Boss Tweed and his three Tammany Ring' associates - New York Mayor Oakey Hall, Peter Sweeny and Richard Connolly - as a group of vultures on a stormy mountain ledge squatting on a body marked 'New York'. They were shown picking over bones with labels such as 'Rent Payer', 'Liberty', 'Law', 'Tax Payer', 'Justice' and 'Suffrage' and above their heads could be seen a lightning bolt about to start a landslide that would sweep them away.

A staunch Republican himself (and a Protestant), Nast - together with Harper's Weekly - campaigned vociferously against William Marcy Tweed, the corrupt leader or 'boss' of Tammany Hall (named after its headquarters on East 14th Street), the political machine which ran New York City's Democratic Party. A former New York State Senator, Tweed and his Irish Catholic associates had by January 1869 taken control of the city, and were looting millions of dollars of taxpayers' money by 'invoice padding', bribes, kickbacks, intimidation and other means. It was said that construction of the Brooklyn Bridge could not proceed until Tweed had got a seat on the construction company's board, and a particular scandal was the massive overspending on the construction of the New York County Courthouse (begun in 1861), which finally cost more than the USA's purchase of Alaska in 1867.

Thomas Nast was born in 1840 in Landau-inder-Pfalz, near Heidelberg in southern Germany. He was the son of a musician in a military band and emigrated to New York with his sister and mother in 1846 (his father followed later). After studying as an artist at the National Academy of Design for three years he started work, aged fifteen, as an illustrator/reporter for Frank Leslie's Illustrated Newspaper. In 1860 he joined the New York Illustrated News and also drew for the Illustrated London News before moving to Harper's Weekly as a political cartoonist in 1861 at the start of the American Civil War. Here he quickly became the magazine's chief artist and, a supporter of the Union cause of the North, was reputedly called by Lincoln Our best recruiting sergeant'. He also famously created the Republican Elephant and the Democrat Donkey - both of which are still in use as US party symbols today - and produced the original (pre-Coca Cola) image of Father Christmas as a bearded old man.