Antique Vintage Horse Harness Single Tree End Bracket, used to hitch to a Wagon, Carriage, or horse-drawn farm implement.  The wooden part of the single tree is long gone.  

This bracket appears to be forged iron, but is possibly cast iron.  The bracket sides have two sets of holes for attaching to the tree / pole end.  The holes nearest the end are open, with one side being squared, as if to retain a carriage bolt.  The back end "holes" are not actually open; they would need to be drilled out to use.  Appears to be flashing in the middle of these back holes, which would be more like a casting issue.  The condition is pitted rusted.  Very "Rustic".  I estimate is from the later 1800's and was used by my great-grandfather on his farm during 1880-1920 timeframe.

This bracket is not the typical Single Tree end bracket, in that the end ring goes to the back as well as the typical front.  So, it may be something else entirely.  Single trees are being pulled in one direction, so would not have to have a loop for attaching harness on the opposite direction.  I have not found any similar bracket currently listed or in Google images.

Length: 10"; width: 4-3/4",  thickness: 1-1/8";  30.5 Oz  (1 Lb, 14.5 Oz)
#0091