at age 73, he journeyed to rest in peace in the Himalaya mountains, the most beautiful place that came to his mind. He wanted to be alone and be unspoken about his death. He wanted to be in Tao and disappear in the Tao.
We do not know what year Laozi (Lao Tzu) died. In fact we do not even know what century he lived in. There are really no contemporary historical records of Laozi, and there is nothing in his work...
His death is unknown. According to legend, he was killed in Faiyum by either wild dogs, Nile crocodiles, or by a hippopotamus. He died at age 63, around 3030 BC.