The Liber de compositione alchemiae ("Book on the Composition of Alchemy"), also known as the Testamentum Morieni ("Testament of Morienus"), the Morienus, or by its Arabic title Masāʾil Khālid li-Maryānus al-rāhib ("Khalid's Questions to the Monk Maryanos"), is a work on alchemy falsely attributed to the Umayyad prince Khalid ibn Yazid (c. 668 – c. 704).
[2][a] The work takes the form of a dialogue between Khalid ibn Yazid and his purported alchemical master,[3] the Byzantine monk Morienus (Arabic مريانس, Maryānus, perhaps from Greek Μαριανός, Marianos),[4] himself supposedly a pupil of the philosopher Stephanus of Alexandria (fl.
[5] Widely popular among later alchemists, the work is extant in many manuscripts and has been printed and translated into vernacular languages several times since the sixteenth century.
[7] The Arabic text belongs to the alchemical works associated with Khalid ibn Yazid, which are widely regarded as ninth- or tenth-century forgeries,[8] although it has also been argued that some of them may go back to the eighth century.
[10] The word alchemia in the Latin title does not yet refer to the art of alchemy, but rather to the mysterious material which alchemists claimed could transmute one substance into another (i.e., the elixir or philosophers' stone).