You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Ottoman_Empire

Context:
Over the course of Ottoman history, the Ottomans managed to build a large collection of libraries complete with translations of books from other cultures, as well as original manuscripts. A great part of this desire for local and foreign manuscripts arose in the 15th Century. Sultan Mehmet II ordered Georgios Amiroutzes, a Greek scholar from Trabzon, to translate and make available to Ottoman educational institutions the geography book of Ptolemy. Another example is Ali Qushji -an astronomer, mathematician and physicist originally from Samarkand- who became a professor in two madrasas, and influenced Ottoman circles as a result of his writings and the activities of his students, even though he only spent two or three years before his death in Istanbul.

Question:
In what century did the Ottoman's start to desire foreign manuscripts?

15th Century