Complex sentence: Through the accession of the German Democratic Republic to the Federal Republic of Germany, effective from 3 October 1990, the territory of the German Democratic Republic became part of the Federal Republic of Germany, today simply known as "Germany".
Split into simpler sentences: Through the accession of the German Democratic Republic to the Federal Republic of Germanyit was effective on 3 October 1990. The territory of the German Democratic Republic became part of the Federal Republic of Germany; today simply known as "Germany".