The Middle Ages are called the time when the development of science stopped. Indeed, since the fall of the Roman Empire and until the Renaissance, there were almost no high-profile scientific discoveries. However, this is not quite true. Progress never stops. It's just that in the Middle Ages, progress concerned the natural sciences much less than more applied things. For example, in the Middle Ages, very progressive methods and tools for cultivating fields were invented, which helped to rid Europe of hunger. And yet, without technological progress, it would be impossible to build huge castles. Dublin Castle is one of them.