The supreme court decision was said to have been 1907. I am not a great researcher and have not found it yet. I did find a supreme court justices comment that the 13th and 14th amendaments created 2 kinds of persons, a freeman and a citizen. A freeman uses land belonging to the noble in exchange for payment. The third kind of person is clearly above, or separate from, the other 2.

Here is what I found:
The primary purpose of the Amendment was originally to protect freed slaves, not corporations.[citation needed] One of the 1886 judges, Samuel F. Miller, considered the purpose of the Amendment in 1872, only six years after the Amendment had become law, when the court was "called upon for the first time to give construction to these articles." In the Slaughterhouse Cases (83 U.S. 36 (1872)), Miller delivered the majority opinion and discussed the Thirteenth Amendment and the Fifteenth Amendment as well as the Fourteenth as follows:

The most cursory glance at these articles discloses a unity of purpose, when taken in connection with the history of the times, which cannot fail to have an important bearing on any question of doubt concerning their true meaning. Nor can such doubts, when any reasonably exist, be safely and rationally solved without a reference to that history, for in it is found the occasion and the necessity for recurring again to the great source of power in this country, the people of the States, for additional guarantees of human rights, additional powers to the Federal government; additional restraints upon those of the States. Fortunately, that history is fresh within the memory of us all, and its leading features, as they bear upon the matter before us, free from doubt. We repeat, then, in the light of this recapitulation of events, almost too recent to be called history, but which are familiar to us all, and on the most casual examination of the language of these amendments, no one can fail to be impressed with the one pervading purpose found in them all, lying at the foundation of each, and without which none of them would have been even suggested; we mean the freedom of the slave race, the security and firm establishment of that freedom, and the protection of the newly made freeman and citizen from the oppressions of those who had formerly exercised unlimited dominion over him.[13]