Technology and science in England advanced considerably during the Middle Ages, driven in part by the Greek and Islamic thinking that reached England from the 12th century onwards. Many advances were made in scientific ideas, including the introduction of Arabic numerals and a sequence of improvements in the units used for measuring time. Clocks were first built in England in the late 13th century, and the first mechanical clocks were certainly being installed in cathedrals and abbeys by the 1320s. Astrology, magic and palm reading were also considered important forms of knowledge in medieval England, although some doubted their reliability.