As a continuation of previous studies about the reception of Rasā’il Ikhwān al-Ṣafā’ in al-Andalus, this paper argues that it was common among Andalusī scholars of the Middle Ages to credit the astronomer Maslama al-Majrīṭī not only with the authorship of Rutbat al-ḥakīm and Ghāyat al-ḥakīm – now both correctly ascribed to Maslama Ibn Qāsim al-Qurṭubī – but also with the entire encyclopaedic corpus of the Rasā’il. The first part of this article seeks to explain the series of successive confusions (...) by which these three works came to be identified as forming three steps of a philosophical ladder and how this trilogy then came to be attributed to the scientist al-Majrīṭī. The second part focuses on two biographical notes found on the title pages of two manuscripts of the as-yet-unedited Rutbat al-ḥakīm. In addition to providing supplementary evidence for the spread of this misconception among medieval scholars, these documents also offer valuable and sometimes unique information about the two Maslamas, their respective writings and entourages, as well as the widespread circulation of the Rasā’il across the Peninsula. The edition, translation and commentary of these two biographical notes are here provided for the first time. (shrink)