Complex sentence: Along with the rest of the Crimean Peninsula, it is considered part of Ukraine by most of the international community, and was a "de facto" and "de jure" city in Ukraine during period from dissolution of Soviet Union to 2014 Crimean crisis.
Split into simpler sentences: Along with the rest of the Crimean Peninsula, it is considered part of Ukraine by most of the international community,. Sevastopol was "de facto" and "de jure" city in Ukraine from the dissolution of Soviet Union to the 2014 Crimean crisis.