]There's one bit in the book we just read, where the Rev. Holland writes in his diary that his servant Robert has taken out the "great horse" and ridden it on an errand rather than walking, and that he will "rot with laziness"- obviously, the reverans didn't really approve of this! I presume that the "great horse" would be a heavy horse- used for carriage work and/or ploughing as well as being ridden.

Great horses are very large horses originally bred, I believe, to carry a knight in his heavy steel armour. We know them as "shire" horses or Belgians. Some breweries maintain these huge brutes to pull their decorative beer keg drays at fairs, etc.

A modern equivalent to Mr. Holland's Robert's riding a great horse where he might have walked would be like driving a bull-dozer when he could have used a bicycle--or walked.