Passage: A constant influx of workers, businessmen and craftsmen from all over Europe transformed Łódź into the main textile production centre of the mighty Russian Empire spanning from East-Central Europe all the way to Alaska. As long as the town was small, the majority of the town's population was German speaking.  Three groups then dominated the city's population and contributed the most to the city's development: Germans, Poles, and Jews, who started to arrive from 1848. Many of the Łódź craftspeople were weavers from Upper and Lower Silesia.

Question: What was Lodz transformed into?
main textile production centre of the mighty Russian Empire