A Sunny Sunday

Sunday-Well you can't do a word history of Sunday without doing a word history of "SUN."
This goes back to Indo European "su-wen/sawel," both, apparently, meaning "sun." Reading various sources, it seems there is no reliable info as to why there are two forms. Just my own "possibility" of why, it could be how the words were used. No matter how ancient the people, the "sun" has always been important, after all, we can't exist without it. Anyway, the Old West Germanic* offshoot from Indo European came from the "suwen" form, giving West Germanic "sunnon." This then gave Anglo-Saxon (Old English) "sunne." This spelling continued for centuries, and it seems that our modern form didn't really takeover until the 1500s. The other West Germanic relatives of English have similar forms: Frisian has "sinne," Dutch has "zon" (as does the German dialect directly across the border, which, not surprisingly, is mutually intelligible with Dutch), many northern Low German dialects have "sünn," and standard German has "Sonne."**

Of course "Sunday" means "day of the sun," and in Anglo-Saxon it was "sunnandaeg." Notice it was not capitalized, and although we take it for granted today, our weekdays did not receive such until the 1600s!!! Our close relative, German, has "Sonntag," and close relative, Dutch, has "zondag," other close relatives, Danish and Norwegian, have "søndag," and Swedish has "söndag."

* The North Germanic languages (and most other Indo European languages) used the other form, "sawel," and this gave Norwegian, Swedish, and Danish "sol," as their word for "sun."

** All nouns in standard German are capitalized.