There are hundreds of different styles of Chinese martial arts, each with their own sets of techniques and ideas. The concept of martial arts styles appeared from around the Ming dynasty (1368-1644). Before the Ming period, martial skills were differentiated only by their lineage. There are common themes among these styles which allow them to be grouped according to generalized "families" , "sects" , "class" , or "schools" of martial art styles. There are styles that mimic movements from animals and others that gather inspiration from various Chinese philosophies or mythologies. Some styles put most of their focus into the belief of the harnessing of qi energy, while others concentrate solely on competition or exhibition.