It is said 2 white doves came into the church during the marriage ceremony..

.. to bless the union of Maximillan (Napoleon’s step-grandson) and Maria (daughter of Czar Nicholas I of Russia).

They had a long and fruitful life in Russia.  Max would become the grandfather of Prince Maximilian of Baden, who would become the Chancellor of Germany in World War I.

(portrait:  an older Maria.. pregnant again and looking none too pleased about it..)