Dattatreya, who is said to be avatar of Tridev, was born in 10th Treta yuga of the current Vaivasvara Manvantra and is believed to have acquired the knowledge of Yoga. In his history, there was no Guru for him but he rather attained the enlightened state by observing 5 elements of nature (Panchabootha), people etc.
Recently I heard he has prescribed yoga shastra for Moksha. Do any of scriptures describe it?