A goof or a misfire?

At one point, General Andre de… says he wants to go to the theater and see Sarah Bernhardt. My guess is that would be around 1870. However, he earlier said that Madame de… fainted for twenty minutes during the Lisbon earthquake, which occurred in 1755. Now, I realize that is supposed to be a joke, but such a line would only be funny if she had been alive at the time, which she clearly was not. But picking an event that occurred long before she was born, he spoiled his own witticism.

In other words, either it was a goof to suggest that Madame de… was alive during the Lisbon earthquake, or it was a joke more likely to confuse than amuse.