Serpents Island was owned by Romania until 1948, when the Soviet Leadership ordered it transfered to Ukrainean control. Presently Romanian asked that Island schould be defined only as a rocky outcropping, and therefore need not be considered important enough to be factor in drawing the Romanian-Ukrainean maritime border.
Ukraine's case was that Island should be defined as an island, which would mean that the continental shelf around it would fall to Ukraine's possesion.