Islamic art
Calligraphic design is omnipresent in Islamic art, where, as in Europe in the Middle Ages, religious exhortations, including Qur'anic verses, may be included in secular objects, especially coins, tiles and metalwork, and most painted miniatures include some script, as do many buildings. Use of Islamic calligraphy in architecture extended significantly outside of Islamic territories; one notable example is the use of Chinese calligraphy of Arabic verses from the Qur'an in the Great Mosque of Xi'an. Other inscriptions include verses of poetry, and inscriptions recording ownership or donation. Two of the main scripts involved are the symbolic "kufic" and "naskh" scripts, which can be found adorning and enhancing the visual appeal of the walls and domes of buildings, the sides of minbars, and metalwork. Islamic calligraphy in the form of painting or sculptures are sometimes referred to as "quranic art".
Quran
In 1972, in a mosque in the city of Sana'a, Yemen, manuscripts were discovered that were later proved to be the most ancient Quranic text known to exist at the time. The Sana'a manuscripts contain palimpsests, a manuscript page from which the text has been washed off to make the parchment reusable again—a practice which was common in ancient times due to scarcity of writing material. However, the faint washed-off underlying text ("scriptio inferior") is still barely visible and believed to be "pre-Uthmanic" Quranic content, while the text written on top ("scriptio superior") is believed to belong to Uthmanic time. Studies using radiocarbon dating indicate that the parchments are dated to the period before 671 CE with a 99 percent probability.
In 2015, fragments of a very early Quran, dating back to 1370 years ago, were discovered in the library of the University of Birmingham, England. According to the tests carried out by Oxford University Radiocarbon Accelerator Unit, "with a probability of more than 95%, the parchment was from between 568 and 645". The manuscript is written in Hijazi script, an early form of written Arabic. This is possibly the earliest extant exemplar of the Quran, but as the tests allow a range of possible dates, it cannot be said with certainty which of the existing versions is the oldest. Saudi scholar Saud al-Sarhan has expressed doubt over the age of the fragments as they contain dots and chapter separators that are believed to have originated later.