 There are various editions of Sanches’s philosophical oevre—in the original Latin with translations into either Portuguese (Carvalho (ed.) 1955; Moreira de Sá (ed.) 1955) or into Italian (Buccolini &amp; Lojacono 2011). To date the only one of his philosophical works that has been published in either English or Spanish translations are Que nada se sabe (Menéndez y Pelayo 1944; Palacios 1972) and Limbrick and Thomson’s That Nothing is Known (1988). In 1940, Joaquin Iriarte discovered a letter from Sanches to Vatican mathematician, Christopher Clavius (1538–1612) in the archives of the Gregorian Pontifical University of Rome. The letter, which was originally published by Iriarte in the journal Gregorianum (1940: 413–451), is also included in Carvalho’s Opera philosophica (in Latin/Portuguese, 1955); in the journal, Cuadernos Salmantinos de Filosofía (1978): with a translation into Spanish, a prologue and notes by Carlos Mellizo and David R. Cunningham (1978: 387–406); and in Buccolini’s and Lojacono’s Latin/Italian Tutte le opere filosofiche (2011); but not in Morerira de Sá’s, Vasconcelos and Meneses Tratados filosóficos (1955). Moreira de Sá, as the editor of the volume, adhered to the initial choice made by Sanches’s offspring of relegating the Clavius letter to his mathematical writings, and the Carmen de cometa to the medical works (both published separately in 1948).