Where does “gang” come from?

I can't write this etymology because the chain you've provided only contains English repeatedly, with no older languages showing how "gang" entered English or where it ultimately derives from. A valid etymology requires showing the word's path through actual historical languages (like Old English, Proto-Germanic, etc.). Could you provide the complete etymological chain with the source languages included?

gang (English): To go; walk; proceed; A number going in company;...