In fact, the model of dhimma as defined in the Quran and in the hadith (the sayings of the Prophet Muhammad) stipulated that while Christians and Jews must pay a supplemental tax in exchange for exemption from military service, they were not to be forcibly converted to Islam. (...) Some descriptive sources from the medieval period (from the seventh through the fifteenth centuries) show that these prescriptions were not always followed. For example, in many cities under Islamic rule, Christians and Jews were compelled to wear specific colors and/or types of clothing in order to physically distinguish themselves from Muslims."
This blog quotes from "Diversity in the Medieval Middle East - Inclusions, Exclusions, Supporters, and Discontents" by Rachel Goshgarian, Chapter 9 in Lucia Volk's The Middle East in the World: An Introduction (Foundations in Global Studies) (Routledge, 2015) on www.academia.edu;; source illustration bywajtu.pl
A proponent of studying Islam based upon its own sources, he commissioned a comprehensive translation of Islamic source material, and in 1142 he traveled to Spain where he met his translators. One scholar has described this as a “momentous event in the intellectual history of Europe.”
The Arabic manuscripts which Peter had translated may have been obtained in Toledo, which was an important centre for translation from the Arabic. However, Peter appears to have met his team of translators further north, possibly in La Rioja, where he is known to have visited the Cluniac monastery of Santa María la Real of Nájera. The project translated a number of texts relating to Islam (known collectively as the "corpus toletanum"). They include the Apology of al-Kindi; and most importantly the first-ever translation into Latin of the Arabic Qur'an (the "Lex Mahumet pseudoprophete") for which Robert of Ketton was the main translator. (...) The translation was completed in either June or July 1143, in what has been described as “a landmark in Islamic Studies. With this translation, the West had for the first time an instrument for the serious study of (and attack on; TN) Islam.”
Source text and illustration Wikipedia