Complex sentence: Many ways in which family relations were conducted during the Han were already stipulated in the ancient Confucian canon (especially in the "Book of Rites"), which became accepted as the mainstream guide to ethics and custom.
Split into simpler sentences: Many ways in which family relations were conducted during the Han were already stipulated in the ancient Confucian canon, especially in the "Book of Rites". This became accepted as the mainstream guide to ethics and custom.