Calligraphic composition in red on a horse chestnut leaf, with a Qur'anic verse in thulth script. Ottoman Turkey, 19th century; length 24.5cm. CAL0165. The Khalili collections © 2011 Khalili Family Trust

The text, part of verse 64 from surah Yusuf (xii), reads: 'But God is the best to take care [of him], and He is the Most Merciful of those who show mercy!