Complex sentence: Montenegro did succeed in liberating and annexing large parts of Herzegovina before the Berlin Congress of 1878, including the Nikšić area; the historical Herzegovina region annexed to Montenegro is known as East or Old Herzegovina.
Split into simpler sentences: Montenegro did succeed in liberating and annexing large parts of Herzegovina before the Berlin Congress of 1878, including the Nikšić area. The historical Herzegovina region annexed to Montenegro was known as East or Old Herzegovina.