I have a sentence:

So admired were these pieces that they encouraged the development of earthenware made in imitation of porcelain and instigated research into the method of their manufacture.

I can't find structure of it. Does "So" in here mean 'too/so much/many'? or is it part of 'so..that'?

What is the structure of "admired were these pieces"? Adj+verb+noun!?