We live in the age of speed. Actually, it has been argued—usually by serious thinkers who are ignored in mainstream and media discussions that speed has been the distinguishing aspect of industrial and now post-industrial capitalism, and that while we have focussed on and even wildly celebrated its advantages, we have often ignored its disadvantages and destructive consequences.
It would have taken at least two days to travel a thousand kilometres by horse. The average speed of a horse is around 40 kmph over longer lengths. So, technically speaking, this could be done in about one day, but obviously, no horse can be ridden without a break for a day, or actually at 40 kmph for more than a couple of hours. Even with a relay of horses, this would take more than a day.

