3. The combination with the participle of the verb substantive,—I have been; thou hast been; he has been.
It is by examples of the first of these three divisions that the true construction is to be shown.
For an object of any sort to be in the possession of a person, it must previously have existed. If I possess a horse, that horse must have had a previous existence.
Hence, in all expressions like I have ridden a horse, there are two ideas, a past idea in the participle, and a present idea in the word denoting possession.
For an object of any sort, affected in a particular manner, to be in the possession of a person, it must previously have been affected in the manner required. If I possess a horse that has been ridden, the riding must have taken place before I mention the fact of the ridden horse being in my possession; inasmuch as I speak of it as a thing already done,—the participle, ridden, being in the past tense.
I have ridden a horse=I have a horse ridden=I have a horse as a ridden horse, or (changing the gender and dealing with the word horse as a thing)=I have a horse as a ridden thing.
In this case the syntax is of the usual sort. (1) Have=own=habeo=teneo; (2) horse is the accusative case=equum; (3) ridden is a past participle agreeing either with horse, or with a word in apposition with it understood.
Mark the words in italics. The word ridden does not agree with horse, since it is of the neuter gender. Neither if we said I have ridden the horses, would it agree with horses; since it is of the singular number.
The true construction is arrived at by supplying the word thing. I have a horse as a ridden thing=habeo equum equitatum (neuter). Here the construction is the same as triste lupus stabulis.