It is related from al-Maʾmun: “Whoever wishes to write a secret letter should write it with freshly-drawn milk, then send it off. He should next take a sheet of paper, burn it, and sprinkle its ashes over the writing; the words will then appear.”

Al-Ṣūlī said: “Al-Maʾmun invented several refinements in the game of chess. He loved to play, yet disliked saying, ‘We are playing,’ and would instead say, ‘We are moving the pieces around.’⦗1⦘”

Yaḥyā ibn Aktham reported: “Al-Maʾmun would hold a public session for debate every Tuesday. One day a man arrived with his garments tucked up and a sandal in his hand. He stopped at the edge of the carpet and said, ‘Peace be upon you.’ Al-Maʾmun returned the greeting.

“The man asked, ‘Do you permit me to draw near?’
‘Come forward and speak,’ the caliph replied.

“He said, ‘Tell me about this position in which you sit: did you reach it by the community’s consensus, or by force and domination?’

“Al-Maʾmun answered, ‘By neither of the two. The one who formerly managed the affairs of the ummah is the one who conferred authority upon my brother and me. When the matter devolved upon me, I realized I had to unite the Muslims around their acceptance of me. I judged that, were I to relinquish the office, the bond of Islam would unravel, their covenant would be confused, they would fall into dispute, the pilgrimage and jihad would lapse, and the roads would become unsafe. I therefore assumed the post as a safeguard for the Muslims until they can agree upon someone they approve, to whom I shall hand the authority.’

“The man said, ‘Peace be upon you, and the mercy of Allah,’ and departed.

“Al-Maʾmun sent someone to find out about him. The envoy returned and said, ‘He went to a mosque where fifteen men dressed as he was were waiting. They asked, “Did you meet the man?” He replied, “Yes,” and informed them of what had happened. They said, “We find no fault with what he said,” and then dispersed.’

“Al-Maʾmun remarked, ‘We have been spared the trouble of dealing with those people in the simplest manner.’⦗2⦘

It is also said that al-Maʾmun retrieved the writings of the philosophers and the Greeks from the island of—