Henry VII’s Book of Astrology (Arundel MS. 66) was completed on 30 June 1490 and is believed to have been made for him. This illuminated manuscript contains astrological tables and treatises alongside other texts, reflecting the late mediaeval and early Renaissance fascination with astrology, divination, and celestial influences on earthly affairs. Its decoration was executed by three artists, whose work ranges from late 15th-century English painting to highly skilled Flemish-style illustrations. An inscription names Johannes Wellys as the presumed scribe. Given that Henry VII was the earliest English king known to have a library, such a lavishly illustrated book on astrology would have been a fitting addition, as celestial bodies were thought to shape human character and events. Among its contents is a richly decorated copy of the astronomical tables of King Alfonso X of Spain (1221–1284), featuring gold-highlighted constellations and stars. The tables detail the latitude and longitude of celestial bodies throughout the year, beginning with Ursa Minor and Ursa Major at the top of the sky, their respective columns adorned with paintings of the bears. The manuscript may have been intended to legitimise Henry VII’s rule through celestial omens or to guide his decisions based on astrological principles. Its pages are lavishly decorated with zodiacal symbols, planetary influences, and astrological charts.