Little is known about the life of Hieronymus Bosch (1450 – 1516), though he was undoubtedly one of the most visionary artists of his era. He was a Dutch painter and his paintings are often of fantastical landscapes and preposterous scenes of the imagination. He is described as "The First Surrealist".
One of his best known paintings is "Garden of Earthly Delights", which is actually several paintings arranged as a triptych with three internal panels, and two external panels that can be folded over the internal panels, making a total of five individual paintings in the triptych. It is believed to have been painted before 1510, but a precise date is unknown, as is its origin.
The external panels, though not erotic, can't be ignored; they're just too beautiful and they also help set the context of the internal panels. The external panels depict a moment during the Creation of the Earth thought to be the third day as described in Genesis. God is sitting in the top left hand corner and at the top of the painting is inscribed in Latin Psalm 33:9 "Ipse dixit, et facta sunt: ipse mandávit, et creáta sunt" which translates to "For He spake and it was done; He commanded, and it stood fast".
As beautiful is the composition is, it does lack color and appears almost monochrome. This is known as a Grisaille style and was popular around Bosch's time, particularly with triptychi. We then open the panels and the triptych explodes with color and movement!
The panel on the left shows God greeting Adam and Eve in the Garden of Eden. The panel on the right shows a surrealistic depiction of Hell. Though what does the central panel show? It doesn't appear to have any religious significance, and there is no religious imagery used at all. It is simply and incredibly orgy of uninhibited nude men and women (mostly women) frolicking in an dreamlike wonderland. Many art historians speculate the meaning of this painting and the general consensus is that it is a warning against lust and indulgence during our time on earth lest ye be cast down into the scenic pits of Hell for all eternity.
But to me, the side panels are only there to add religious context to the central panel. Using this religious context, Bosch was able to create an epic erotic painting (whilst avoiding the censors) that no other artist during the Early Renaissance even came close to matching. It is an incredibly significant painting to the genre of erotic art.