Who is Tzu-yu from The Analects and what is their importance?

Tzu-yu is a disciple of Confucius about whom little is known except that he studies under Confucius after Confucius' return from travels in 484 B.C. Tzu-yu is the disciple who identifies the Way with music and rites. The beginning of excessive emphasis on conformity to rites starts with him. He is critical of other disciples for concentrating on menial duties to the extent of becoming ignorant of what is basic. He is in the group of disciples that cause the Confucian school to split into eight sects.