From: Baha'i Historical Facts
Bahá'u'lláh departed from Tihran for Iraq on 12 January
1853. Among those who accompanied Him in His exile was His eldest son,
nine-year-old Abbas, who later assumed the title of Abdu'l-Bahá (Servant of
Baha). He had such spiritual insight that, as a young boy, He intuitively
recognized the station of His Father. So highly did Bahá'u'lláh esteem Him that
in Baghdad He used to address Him, while still in His teens, as the Master -- a
designation which Bahá'u'lláh had also used for His own father while in Tihran. (Adib
Taherzadeh, The Revelation of Baha'u'llah v 1, p. 13)
