Grotrian’s business interests took him to Moscow, where he established a successful retail concern. When he returned over a decade later to his native Germany, he founded a new piano-making partnership with Heinrich’s son, Carl Friedrich Theodore Steinweg. The moved production to Braunschweig and forged a successful business making quality pianos.
Heinrich Steinweg, meantime, have emigrated to America, change his name to Steinway and established his own company. In 1865, Heinrich died and Theodore Steinweg sold his shares and emigrated to America to run the now flourishing Steinway firm.
Dates and serial numbers when the pianos were manufactured