"The Time Traveller's Guide to Elizabethan England" is a masterwork penned by Ian Mortimer. Ian Mortimer is a historian who has written many historical novels. The Time Traveller's Guide to Elizabethan England is one of them. The writer has used diary entries, letters, and other works of the day to write this book.
There are two ideas that the writer has picturized in the given passage.One is that a flat field was an easy land for farming and agricultural purposes and second, hills and mountains were a difficult track of traveling for travelers. For people today, hills and mountain climbing is a form of adventure whereas, in those days, it was considered an obstacle.
