The bodhisattva Guanshiyin, also known as Guanyin, comes from the Sanskrit word Avalokitesvara. In Buddhism, Guanyin is one of the top-ranking bodhisattva under principal buddha Amitabah in the Pure Land. Along with Amitabah and Mahasthamaprapta, these three are often called the ‘trinity’ of Buddhism.
Guanyin was already a Buddha in a past life, known as “Tathagata of Brightness of Correct Dharma”. In the “Longer Sukhavativyuha Sutra” (Infinite Life Sutra), it is recorded that Guanyin and Mahasthamaprapta both are candidate buddhas of the Pure Land after buddha Amitabah.