Imam Reza's (AS) Martyrdom and Burial

A year after appointing the Imam as his Crown Prince, Ma’mun realized that his plots against the Imam were unsuccessful. The only benefit from his decision during this time was a temporary halt in the Alavid uprisings against his government. Ma’mun could not defame the Imam nor justify his decisions using the Imam’s name, as the Imam always kept himself distant from Ma’mun and his government. With his wise actions, the Imam made his position an invaluable opportunity to spread Shia theology through the Islamic territory. Ironically, the main positive outcome from the Imam’s appointment as the Crown Prince was that after decades of hostility against the Shia Imams, for the first time, the Islamic caliph and the government had to confess to the elevated status of the Shia Imams. This outcome proved the authenticity of the Shia theology to the Muslims around the Islamic territory and accelerated their familiarity with it. Across the Islamic territory, the Imam was regarded with respect as the Crown Prince. The Shias, who had always hid their belief in fear for their lives, were now proudly declaring and spreading their belief. Ma’mun had hoped to disgrace the Imam’s divine character by affiliating him to his government, and was now witnessing the opposite outcome from what he had intended. The Imam’s interactions with the people filled their hearts with love and respect for him to an extent that many of the people believed that the Imam had much more merit for the caliphate than Ma’mun. Also, the Imam’s debates with the greatest Muslim and non-Muslim scholars of the time proved his divine knowledge to the people. Therefore, Ma’mun could not find any way to stop the Imam other than to kill him.
One reason Ma’mun rushed to kill the Imam was the instability in Baghdad, the former capital of the Abbasids. The Abbasid royal family was outraged by Ma’mun’s decision to appoint Imam Reza as his Crown Prince. They could not tolerate seeing the Abbasid government fall into the Alavid lineage in the future. They selected Ibrahim ibn Mahdi, one of their family members, as their chosen caliph and paid allegiance to him. Ibrahim ibn Mahdi was a corrupt character who was famous in public for his singing and intoxication.
Ma’mun decided to move to Baghdad to manage the instability in the city. He knew that the Abbasids would never approve of the Imam as the Crown Prince. They also considered Ma’mun’s minister, Fazl ibn Sahl, as their enemy and held him responsible for Ma’mun’s wars with Amin, whom they had supported. Ma’mun believed that the Abbasids would still accept him as their caliph if he could address their excuse by killing both the Imam and Fazl ibn Sahl.

Martyrdom
Ma’mun wanted to prepare a favorable environment in Baghdad ahead of his arrival, so he decided to eliminate Imam Reza and Fazl ibn Sahl without delay. Shortly after leaving Merv towards Baghdad, his caravan arrived in Sarakhs, which is the current day border between Iran and Turkmenista