It was one of the only fashionable coats made with three seams (no side body piece) after ca. 1840. The details ebbed and flowed once a rather ill fitted version had taken hold by ca. 1860 through past the end of the century. For basic shapes, I actually started with an 1860s sack coat pattern that kinda-sorta fit and worked from there. Widened the collar and lapels by 3/4", shaped the area between the second to top button and start of lapel fold to better fit my chest, slightly more heavily interfaced the chest, re-shaped the sleeves (the early 1860s fashionable sleeve was very wide) based on some extant pieces in my collection with a similar shape that I was going for, introduced a body fish between the armsye and pockets with help from page 108 of The Victorian Tailor by Jason MacLochlainn, and introduced a ticket pocket above the right hip pocket (also with some help from MacLochlainn's diagrams). The ticket pocket pocket occurring more often than not in a variety of primary documentation from the 1880s. I moved the breast pocket slightly but next time need to adjust the angle. I also used a cotton/linen blend canvas for interfacing and regret not using hair canvas; will not make that mistake again. Some primary documentation to back up my decisions:
Beginning of the general look- Bat Masterson, ca. 1879.
Ca. 1880s, Patterson Homestead in Ohio, via my friend Katie Nowack.
Ca. 1889-1890, J. Mitchell Co., New York, Fall-Winter.
Ca. 1890 via freeuk.com
Extant suit conforming to general characteristics via Augusta Auctions.
By the end of the 1890s, styles were changing again (as they do), with the most conspicuous difference being a more dramatic slope to the front bodies: