Sykes' History of Persia Vol 2 (pdf) - Heritage Institute

I
THE GOLDEN AGE OF ISLAM 73
Merv to warn him of the dangerous position of affairs,
but owing
to the influence of the Vizier he was not
allowed even to speak, but was hurried off to prison,
where he died.
The Proclamation of AH Riza as Heir-Apparent, A.H.
20 1
(817). To meet the crisis the Caliph took an extraordinary
step.
In the hope of putting an end to the
insurrection, he appointed as his heir-apparent Ali Riza,
the head of the House of Ali, although he was twentytwo
years older than himself. He promulgated an edict
directing that allegiance was to be sworn to the Imam
Riza, as he is
generally termed, and in order to mark the
new departure he ordained that the green of the Shia
was to be substituted for the black of the House of
1
Abbas. The Shias were enraptured, but at Baghdad the
people rose in fury to depose Mamun, and his uncle
Ibrahim received homage as Caliph. When news of this
serious occurrence reached Merv, Ali Riza had the nobility
to warn the Caliph that his policy would break up the
Empire. Mamun, realizing the truth at last, gave orders
to march on Baghdad, and Fazl was assassinated in his
bath at Sarakhs, probably by order of his master.
His Sudden Death, A.H. 203 (818). At this time the
Caliph gave one of his own daughters to Ali Riza and
a second to Ali Riza's son, while as a further mark of
favour he conferred upon one of his brothers the high
honour of presiding at the annual pilgrimage to Mecca.
But the catalogue of his distinctions came to an abrupt
close. The Imam Riza died suddenly from a surfeit
grapes and was buried under the same dome as
Raroun-al-Rashid. Rumour, accepted as truth by the
ias, represented that the grapes were poisoned, and it
mot be denied that the heir-apparent's disappearance
was extremely opportune. Nevertheless, many eminent
Orientalists, Beveridge among the number, believe that
he died a natural death. Be this as it
may, Shia pilgrims
at the present day, when moving
in procession round the
tomb of Ali Riza, pause to cry out " Curses on Haroun
1
In The Glory of the Shia World, p. 237, I have described the whole event from the
Shia point of view.