click on the image to enlarge.
This particular breastplate has many important points of interest. From a distance, you can see that stylistically, it is meant for a foot soldier....though of course the narrow sides mean it can ride up high when you sit a horse. There is a total lack of lance rest, or even a place to mount a lance rest. It must have been grand with the leather picadills all around the arm holes and the bottom...and comfortable to wear as well! Note the fact that the beautiful rolled edges are not roped in any way.
On the front, there are two high shoulder rivets a hands width from the top...they are designed to hold a heavy placqart, a haute piece if you will, which will be much heavier and able to deflect a bullet. So this armour is not just a parade piece of armour, but rather, a serious battle armour. That it was used in parade is evident from the delightful repousee'd crucafix on the front. Repousee would not remove any metal,whereas engraving chisels metal away, weakening it. One sees both on this armour.
The armour was originally hammer welded in the belly, and due to heavy use (as indicated by the dents around the shoulder rivets as well) it cracked at the weld. It might have been that the armour was made from that new fangled steel instead of good old iron, and steel is notoriously difficult to weld on the hammer. So the armourer sunk 4 rivets on the belly to hold the two overlapping placquart pieces together, and a couple more to hold a backing plate to the flare below. This would have made the armour satisfactory for battle, and as long as the knight wore a nice wide sash around his waist over his armour, the repair would be nearly invisible.
There is no doubt much more about the provenance of this armour that we can deduce from the repairs, and the styles, and maybe there are even paintings showing a knight wearing exactly that armour. It would not be cheap armour, so a painting might exist!