Many letters in this field were exchanged between Al-Ma'moon and Imam Ar-Ridha “a.s.”. Imam Ar-Ridha “a.s.”, expressed his rejection of the tenure, while the Calipha was insisting on him to accept it. The successive letters bring about nothing, while Imam “a.s.” frustrated the demonic plot of the Calipha through his vigilant position, and all his attempts were fruitless, and the Imam declared his refusal of Al-Ma'moon’s quest.
Maamun alipoona kwamba kwa upande wa barua hakuna dalili za mafanikio aliamua kumtuma Rajai ibn Abi Dhahakar kwa Imam (a.s) ili amshawishi na aje naye katika mji wa Marw uliokuwa makao makuu ya serikali yake. Rajai alipomwendea Imam na baada ya kumalazimisha Imam (a.s) alilazimika kutoka katika mji wa Madina lakini kabla Imam hajaondoka katika, aliamua kufanya ziara katika kaburi la babu yake Mtume (s.a.w) na maimamu na wengine katika makaburi ya Baqi, Kisha aliwaaga wanae na nduguze wa kike na kiume akiwemo miongoni mwao dadake mpendwa Sayyida Fatimah Maasumah (a.s).