The school consisted of calligraphers, illustrators, transcribers and translators, who collaborated to produce illuminated manuscripts derived from non-Arabic sources. The characteristic Baghdad School artistic style, which features sprightly characters bearing highly expressive faces and hand gestures (rather than stereotypical people), reached its peak in the first half of the 13th-century, although some examples can be identified at earlier periods.[3] Illustrations in this style represent a skilful blend of Byzantine, Persian and Arab features.[4]