The Mighty Bishops of Konstanz – and a Duke?

If you go to the German city of Konstanz you’ll find some imposing statues along the Rhine River:

OK, so let’s have a quick look at who these guys were. Unbelievably, three of them are bishops that lived and died a long, long, long time ago.

Here is Bishop Berthold, who died in 1078:

Here is Bishop Gebhard, who died in 995:

And finally, here is Bishop Conrad, who died in 975:

But who is the fourth guy?  It’s Leopold, the Grand Duke of Baden, who died quite recently, in 1852:

Quite an interesting conundrum. Was this a vanity project commissioned by the Duke before he died, to have his statue next to these old guys?

Somebody must know – but not me!