The term hilya (Arabic حلية (plural: ḥilan, ḥulan), Turkish: hilye (plural: hilyeler) denotes a religious genre of Ottoman Turkish literature, dealing with the physical description of Muhammad. Hilya literally means "ornament".
They originate with the discipline of shama'il, the study of Muhammad's appearance and character, based on hadith accounts, most notably Tirmidhi's al-Shama'il al-Muhamadiyyah wa al-Khasa'il al-Mustafawiyyah ("The Sublime Characteristics of Muhammad").
In Ottoman-era folk Islam, there was a belief that reading and possessing Muhammad's description protects the person from trouble in this world and the next, it became customary to carry such descriptions, rendered in fine calligraphy and illuminated, as amulets. In 17th-century Ottoman Turkey, hilyes developed into an art form with a standard layout, often framed and used as a wall decoration.
Later hilyes were also written for the first four Caliphs, the companions of Muhammad, Muhammad's grandchildren (Hasan and Hussein) and Islamic saints (walis).
Hilye, both as the literary genre and as the graphic art form, originates from shama'il, the study of Muhammad's appearance and character. The best source on this subject is considered to be Imam Tirmidhi's al-Shama'il al-Muhamadiyyah wa al-Khasa'il al-Mustafawiyyah ("The Sublime Characteristics of Muhammad"). The acceptance and influence of this work has led to the use of the term "shama'il" (appearance) to mean Muhammad's fine morals and unique physical beauty. As they contained hadiths describing Muhammad's spirit and physique, shama-il have been the source of hilye. The best known and accepted of these hadith are attributed to his son-in-law and cousin Ali. The sources of hilye have been the six main hadith books along with other hadith sources, attributed to people such as Aisha, `Abd Allah ibn `Abbas, Abu Hurairah, Hasan ibn Ali. While shama'il lists the physical and spiritual characteristics of Muhammad in detail, in hilye these are written about in a literary style.