I believe this to be an 1860s era CdV, due to the square corners, general sparsity of props and absence of a back mark. What I have read is that in the earlier part of the decade, little to no props were used, but by the end of the decade, chairs, tables and other assorted props had become popular. I find the curtain to the right of this gentleman quite strange. What could it possibly be covering that couldn’t have been moved out of the way? Also of note is the dark shadow behind his feet, which I believe to be the base of a positioning stand. Holding onto the chair and with a positioning stand behind, it was far easier to stand still for the long exposure time during early photography.