While descendants of Heinrich, through his grandson, Jakob, came to America in the 1850s (see the line of Johann Georg Altstadt (1831)), others moved abruptly in the same time frame to Austria. The reason for the move to Austria was a political one. Andreas Altstadt was a servant of the Graf Orttenburg. The Graf, which held the title, was about to be displaced by his brother. Andreas and some "trusty" citizens tried to stop the treason and planned a revolution against the brother. The brother got knowledge of that and they had to run for their lives. As Ortenburg has relatives near Vienna, they went there and changed their surname spelling to Allstadt.
This Allstadt line moved back into Germany in the 20th century settling around Nuremberg.