Amphora 1906-1910 Vase

Just bought this from a friend, but I don’t know much about it. I fell in love with Amphora pottery I saw when user AmphoraPottery posted photos. That was my first exposure. I’d never heard of it before. So I started looking at it on Facebook. Good Lord, it’s expensive! When I had the opportunity to buy this piece at a price that I could afford, I jumped on it. I would love to know more about it. When was it made. Where? Any specific maker? EDIT: The marks belong to the Amphora factory, but the central mark comes after Alfred Stellmacher left his partnership with Riessner and Kessel in 1905; the firm name then became 'Riessner & Kessel "Amphora".' The piece dates probably to c. 1906-10, but maybe a little later.