Humanist Treatise.- [Isabella Sforza (Lady, author, natural daughter of Giovanni Sforza, Lord of Pesaro, wife of Cipriano del Nero, Lord of Porcigliano, 1503-61)] [Of the True Tranquillity of the Soul], translated by an unidentified English translator, manuscript in Elizabethan English, 111pp. excluding blanks (prologue 5pp., text 103pp., epilogue 3pp.), in a clear and legible Secretary hand, on paper, in light brown ink, ruled in light red ink, 55ff. water-stained (some slight and some with tide-lines) but all still legible, slightly browned, engraved cutting of the Curriers Livery Company on front free endpaper, original vellum, gilt diamond centre piece and corner pieces with a double line rule border, gilt initials "CL" on lower cover, damp-stained, upper cover with small piece of edge torn away, creased, soiled and splayed, lacks ties, lower cover in better condition but still creased and with a large brown mark, gilt panelled spine, 150 x 110mm., [England], [c. 1580].*** "...behold this booke this booke (I saye) presents unto us, that invaluable pearle of Tranquilitye, which, like the euer florishinge bay tree, can neuer be touched with any thunderbolts of adversitye." - Translator.A hitherto unknown translation of Isabella Sforza's Della vera tranquillita' dell'animo, first published in Venice, in 1544. The humanist treatise includes chapters on the "Dignity of Man"; "the principal passions"; "refraining from anger"; "to tame gluttony and wantonness"; "lay aside pride"; "tranquility" etc. The published work has twelve chapters, but the translator must have been working off an incomplete copy as this manuscript lacks chapter twelve. In his epilogue he writes, "Here, I am inforced to make an abrupt connexion of that wch followeth bicause there wanteth two leaves in the Originall; as though the starrs did envye the good of mankinde". The translator, as yet unidentified, has dedicated the work to his "deare mother" and writes that he "was imboldned to make choyse of this booke, bicause it is a worthy monument, both of a woman and a Ladye; Where by the waye I must needs note their irreligious, and unpardonable error, who being possessed with the spirit of slander, haue presumed to call women… errours of Nature: To these men (if I may lawfully call them men, who haue so disnaturd themselves, as to defame that sexe ?such is the principall cause; that they are men) to these men (I saye) to omitt all others, I will onelye urge the inimitable example of the noble Italian Ladye Isabella, the learned foundres of this neuer inough admired treatise. Shee was a woman; true but yet learned: indeed a wonder... ." The translator mentions few personal details but records twice "that it was gods will, that my lands and possessions should be... taken from me... ."