Complex sentence: I. J. Singh states that throughout Sikh history, there have been many subsects of Sikhism that have espoused vegetarianism however, this was rejected by the Sikh Gurus.
Split into simpler sentences: I. J. Singh states that throughout Sikh history, there have been many subsects of Sikhism that have espoused vegetarianism. However, this was rejected by the Sikh Gurus.