Complex sentence: The "Kessel" or pocket was located near Heiligenbeil (Mamonovo) in East Prussia, and the battle, part of a broader Soviet offensive into the region, lasted from 26 January 1945 until 29 March 1945.
Split into simpler sentences: The "Kessel" or pocket was located near Heiligenbeil (Mamonovo) in East Prussia. The battle lasted from 26 January 1945 until 29 March 1945.