I need to start a sentence by saying that something has been known for a long time. What is the most elegant way of writing that? Two possibilities that come to my mind are:
1) It has been known since long time that ...
2) Since long, it has been known that ...
Personally, I prefer the second option. The first sounds ugly to me. But since I'm not a native English speaker, I would like to ask for suggestions of what would be the best way of saying that. Please feel free to suggest other forms.