 Avicenna did not treat all of these subjects in each one of his summae, but he varied their contents and emphasis depending on the specific purpose for which he composed them. He developed a style of supple Arabic expository prose, complete with technical philosophical terminology, that remained standard thenceforth. After The Cure, he was asked to write a brief exposition of the philosophical subjects, which he did by collecting and putting together—at times even splicing together—material from his earlier writings and produced The Salvation (al-Najāt). He did the same, in Persian this time, for his patron the Kakuyid ʿAlāʾ-ad-Dawla, the Philosophy for ʿAlāʾ (Dāneshnāme-ye ʿAlāʾī, GS 7). In both of these books he left out the mathematical sciences and the subjects of practical philosophy, only the former of which was later supplemented by Jūzjānī, first in Arabic and then in Persian, on the basis of earlier writings by Avicenna.