Aljamiado in the context of Mancebo de Arévalo

The Arabic script is the writing system used for Arabic (Arabic alphabet) and several other languages of Asia and Africa. It is the second-most widely used alphabetic writing system in the world (after the Latin script), the second-most widely used writing system in the world by number of countries using it, and the third-most by number of users (after the Latin and Chinese scripts).

The script was first used to write texts in Arabic, most notably the Quran, the holy book of Islam. With the religion's spread, it came to be used as the primary script for many language families, leading to the addition of new letters and other symbols. Such languages still using it are Arabic, Persian (Farsi and Dari), Urdu, Uyghur, Kurdish, Pashto, Punjabi (Shahmukhi), Sindhi, Azerbaijani (Torki in Iran), Malay (Jawi), Javanese, Sundanese, Madurese and Indonesian (Pegon), Balti, Balochi, Luri, Kashmiri, Cham (Akhar Srak), Rohingya, Somali, Mandinka, and Mooré, among others. Until the 16th century, it was also used for some Spanish texts, and—prior to the script reform in 1928—it was the writing system of Turkish.

Crypto-Islam is the secret adherence to Islam while publicly professing to be of another faith; people who practice crypto-Islam are referred to as "crypto-Muslims." The word has mainly been used in reference to Spanish Muslims and Sicilian Muslims during the Inquisition (i.e., the Moriscos and Saraceni and their usage of Aljamiado). With the Portuguese Empire's expansion to the Far East and the Spanish Empire's spread to the Philippines from Latin America, Filipino Muslims and Portuguese Muslims were also subject to the Inquisition, one famous case being Alexo de Castro of the Spanish-occupied Moluccas, who was tried for crypto-Islam a continent away before the Mexican Inquisition.