This type of cast brass buckle features a spread-winged eagle with a shield on its breast gripping an olive branch. It is a Federal rectangular eagle/wreath waist belt plate, typically an early war specimen. The belt plate shown in the image, specifically identified as a Civil War Union Officer's Eagle Sword Belt Plate, was primarily worn by Northern (Union) soldiers, particularly commissioned officers in the Union Army. However, it is also noted that some Confederate officers used these plates, often due to capture or battlefield acquisition, as the South had less centralized military equipment manufacturing. I picked this up at an estate sale and was told it came down to the deceased via his great, great grandfather. The tooled leather belt bears the initials of the man who passed so this is definitely newer. Nice vintage patina. I am not an expert, I can’t authenticate but every where I checked it appears to be from that time.