A Raga must evoke a particular emotion or create a certain mood. Each Raga has a specific name. It also has a character, which can be devotional, erotic, bold and valorous, or even tragic. Time of day, when it is best performed, is usually specified as a 3-hour interval. However the beauty of the Raga is not affected if it is performed at other times of the day. Some Ragas are related to seasons, for example, Raga Malhar. Ragas are not static. Some can be traced back to ancient or medieval times, others originated only a few centuries or even a few decades ago. However, all Ragas have undergone transformations over the centuries. Many of them have fallen into disuse.