From Qum the Imam moved north to the town of al-ray...

From Qum the Imam moved north to the town of al-ray, the Greek Rhages, which is near the site of the present city of Tehran. From this place the caravan continued its journey until it reached the city of Tus. From Tus they travelled on to the city of Merv, in what is now modern Turkistan. On his arrival in Merv, Mamun welcomed him with great ceremony and pomp. Mamun treated the Imam with great honor.

It is mentioned by various historians, Both of Shia and Sunni schools of thought, that when Mamun initially offered the Imam his throne, the Imam declined the offer firmly and resolutely. After several attempts to bring the Imam to accept the offer failed, Mamun told him to accept the offer of being his heir- apparent to succeed him after Mamun’s death. Imam replied to this offer, “ I will accept this to console you, but this will never happen for I will leave this world before you.”…