Original: In the Nath tradition, Dattatreya is recognized as an Avatar or incarnation of the Lord Shiva and as the Adi-Guru (First Teacher) of the Adinath Sampradaya of the Nathas.
Simplified: In the Nath tradition, Dattatreya is seen as an Avatar or incarnation of the Lord Shiva and as the Adi-Guru (First Teacher) of the Adi-Nath sampradaya of the Nathas.