Later Potemkin ordered the shipyard to be named Nikolaev to commemorate the date of fall of Ochakov to the Russian troops under his command on December 6 , 1788 , close to the day of Saint Nicholas ( Nikolay ) December 19 , in the Russian Orthodox Church . Later Potemkin ordered the shipyard to be named Nikolaev to commemorate the date when Ochakov fell to the Russian troops under his command on December 6 , 1788 , close to the day of Saint Nicholas ( Nikolay ) December 19 , in the Russian Orthodox Church calendar .