Charlemagne receiving the gift of a clepsydra (water clock) from Harun al-Rashid, c.1910 (colour litho)

Emperor Charlemagne was sent a brass water clock and other gifts by the Abbasid Caliph, Harun al-Rashid in Baghdad; Charlemagne (742-814), first Holy Roman Emperor, and the first emperor in western Europe since the Roman Empire; he was the first Germanic ruler to be granted the title of Emperor by the Church and to be recognised as such by the Eastern Roman Emperor (based in Constantinople) and also the Muslim world, shown here by the illustration of the embassy sent to Aix-la-Chapelle (Aachen) from Baghdad by the Caliph Harun al-Rashid (763 / 766 – 809), the fifth Abbasid Caliph; Charlemagne reciprocated Harun's gifts by sending horses, Frisian cloaks and hunting dogs;