Those eagle buttons are nice. US military buttons. Generally one piece is older, something like 1820s-40s, and two piece is more like 1860s-80s. Those aren't hard dates though. If the shield has a letter in it, it means the person that wore it was part of a specially unit (I for infantry, C for Calvaly, A for Artillary etc.). If there is no letter it is a general service button.