Jag går tillbaka till sängs.

[davidculley]

English Translation

I’m going back to bed.

Why is a “s” needed at the end of the word “sängs”?

[morbrorper]

It’s a remnant of the old rection system; in old Swedish, “till” used to be followed by the genitive. Now it’s only preserved in a few set expressions. These are some examples that come to mind:

• Till sängs.
• Till bords.
• Till havs.
• Till sjöss. (note the spelling)
• Till fots. (But: “till häst”)
• Till buds.
• Till vardags.
• Till lags.
• Till dess.

[davidculley]

Thank you so much, @morbrorper!

Searching the forum for “till genitive” leads you to these similar sentences:

Han känner sig illa till mods.

“He feels uneasy”. “till mods” is a set expression that is used to describe one’s mood. Grammatically it is interesting because “mods” is the genitive of “mod”; it is one example of a handful of Swedish set expressions that use “till” plus the genitive - other examples are “till fots”, “till bords”, “till sjöss”, to name a few.

The genitive is not just used after “till” but also after “i”:

Han var sjuk i söndags.

The genitive after i is a remnant from the old days, when the language had four cases, with different prepositions requiring different cases, similar to modern German. The same goes for genitive after “till” in some set expressions: “till sjöss”, “till fots”, etc. I don’t know why, but it prevents a lot of misunderstandings.