I have a gg-uncle, John Luther Martin, who at the age of 50 in the Spring of 1862 joined the 1st Missouri Cavalry (Gates) (CS), later the 1st Missouri Cavalry Dismounted (CS) and a part of Green's Brigade during the Iuka/Corinth and Vicksburg Campaigns. Ol' John Luther finally wore out during the siege of Vicksburg and was confined to a hospital ship at the surrender of Vicksburg and died shortly thereafter.
Now I'm 57 and I can't imagine riding off to war in my 50's and enduring the hardship he must have from April of 1862 through July of 1863. Tough old guy, Uncle John Luther, don't you think?
Jim