'Aniline' was first isolated by a German chemist in 1826. In 1834 another German discovered a coal tar derivative that produced a bright blue color which he called cyanol, but the first commercial aniline dye was produced in 1856 by William Perkin, who discovered mauveine, an aniline compound that produced the color 'mauve'. Perkins is usually given the credit for aniline dyes, although he was simply the first commercially successful product, because at the same time the German chemical industry discovered way to produce aniline compounds by the ton and started a massive artificial dye industry.
The most notorious of the new colored dyes was "Paris Green", a bright, deep green used on a gown worn by the French Empress Eugenie in 1864. It was all the fashion rage after Empress wore it, but the dye was composed by mixing copper and arsenical compounds, so that if someone wore a garment so colored, they got arsenic poisoning to various degrees. 1/8 of a teaspoon constitutes a fatal dose of arsenic, and the average green Victorian era dress might have several pints of dye on it.