Theory:

No.
Words
Meanings
1
classicjudged over a period of time to be of the highest quality
2
harnessedfixed a set of straps by which a horse is fastened to a cart
3
sturdystrongly and solidly built
4
tollgatea gate across a road or bridge where travellers must stop and pay, to proceed
5
groana deep sound, especially due to some damage
6
bridlea set of leather straps tied around the neck of a horse to control it
7
calmed my nervesto stop from getting nervous, to pacify
8
tremblingshaking, due to fear/anxiety
9
a dead stopa complete, sudden stop
10
whip
(noun) a strip of leather attached to a handle, used for urging on an animal
11
trottedran with short steps, moved faster than a walking pace
12
stillernot moving or making any sound
13
instinctan innate, typically fixed pattern of behaviour in animals in response to certain stimuli
14supperan evening meal, typically a light or informal one
15gratefulthankful