October 7, 1920 Poland signed the Suwalki Treaty with Lithuania, recognizing the Vilnius region as part of Lithuania. However, two days after the signing of this treaty, Poland broke the agreement and seized Vilnius and the Vilnius region, which it ruled until 1939.
October 27-29, 1939, after 19 years of occupation of the Vilnius region, the Lithuanian army entered the Lithuanian capital.