In the 1850s (I think I have the date right) Yale put the kibosh on the
establishment of a college for African-Americans in New Haven. Yale feared
that the mere existence of such a school down the street would alienate
alumni and students from the slaveholding states. This information was
turned up several years ago when a group of researchers looked into Yale's
connections to slavery. Their report can probably be found online somewhere.
I don't know if further research has been done since then. 

Henry Wiencek