Fountain of Knowledge

These are the things that keep me up at night...

What were good quality mattresses made from in the late 1500, early 1600's? Were they firm or soft or somewhere in between?

The next is on naming landmarks. My characters are in Montreux on the shore of Lake Geneva in Switzerland, looking at the Chateau de Chillion. There are two problems with this - Lake Geneva's real name is Lac Léman and Chateau de Chillion, in English should be translated to Chillion Castle.

I would prefer to keep the names of the two landmarks in their original French, but what is the standard rule people go by? Should I translate them both? Translate the lake and not the chateau? Most people would know what a chateau is, but a lot of non-Europeans have no idea that Lake Geneva isn't really called Lake Geneva.

If I obsessed this much on the actual story I would be done by now.

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