This notion of climate zones was picked up by medieval geographers and was in use during the 13–18th centuries. In the 13th century, Roger Bacon, considered to be the first English scientist, wrote (in Latin) that Ptolemy of Alexander (second century AD) distinguished numerous ‘climata’ marking them by the increasing length of the longest day. These are defined by an increase of 15 min to latitude 61°, then 30 min to 64° and then by an hour to 66° latitude