the story of ugliness.    "Beauty is ugliness and ugliness is beauty". -Macbeth act 1

Down the centuries philosophers and artists have put together and offered us definitions of beauty. Thanks to their work and reflections, over time we have been able to see and examine how the aesthetics of beauty have been constructed. But this has not happened with ugliness. Ugliness has always been taken to be "the opposite of beauty", but is has hardly been studied in its own right. So it is difficult to look into the history of ugliness as it does not exist, not in the way that the history of beauty exists, with clear theoretical, philosophical and artistic bases. Because of this, we should not forget that whenever we talk about ugliness that, in fact, we understand this idea as being the opposite of beauty.
Art is the best place to get to know each period's idea of beauty - and of ugliness. When we say art, we are talking about the development of western and Asian art. When we use the word "development", we mean the theoretical processes that this art accepts and so we are talking about means of measuring and classifying. The arts of primitive civilizations have not created theoretical developments, and we cannot measure their artistic creations using our aesthetic senses or ideas. This does not mean that beauty and ugliness do not exist in primitive civilizations. The only way we can understand them is by making an effort to accept them. In the mentioned "developed" cultures and civilizations, down the centuries, and for worse and for better, religion has had a lot to do with artistic creation. Different ways of reflecting humanity's beliefs have formed the definition of ugliness. The idea of evil reached prehistorically society due to fear. Living in the middle of the food chain meant living in fear for thousands of centuries. This fear was caused by synonyms for evil (natural and meteorological phenomena, unknown peoples, etc). The classical civilizations felt the need to give bodies to the evil they described in their myths. And so they created monsters. As well as being symbols of evils, monsters became the opposite of beauty. And to continue on a moral and religious line, ugliness was a physical reflection of illness of the soul. Ugliness became a synonym of evil and was thought to mark sinners and penitence.
After the Middle Ages, little by little fear of ugliness and only associating it with evil began to be left behind, and it began to be linked with other sensations. As beauty started to become one of society's values, what was not beautiful caused feelings of sadness, marginalization and pity as well as just fear.
Nietzsche, Kant and numerous other philosophers touched on the idea of ugliness in passing, always starting from a religious or moral point of view. Karl Rosenkranz was the first person to write directly and in depth about the subject. In 1853 he published Aesthetik des Hässlichen (The Aesthetic of Ugliness). In the 20th Century artists proclaimed ugliness to be a value. A few had done this before (Hieronymus Bosch, for example), but this actually became a tendency during the last century. Essays and reflections about beauty and ugliness appeared and, as Macbeth's witches had foreseen hundreds of years before, the age of the beauty of ugliness had arrived.
But the definitions of beauty and ugliness cannot be fixed on purely aesthetic lines. Political and social reasoning have also been extremely important throughout history. Economics, for instance, have been extremely important in this area. Marx stated clearly that " money, from the moment in which it can buy everything, buy beauty or ugliness, makes it possible for anything to become beautiful". It is a subject of great interest and is related with many other issues. Umberto Eco brought many of them together in a beautiful book about ugliness: Storia della bruttezza (On Ugliness).