Phonetic transliteration of a 'Saint Lawrence' fortress/castle name.
圣 = 'Saint',
罗伦斯 = 'Lawrence',
堡 = 'fort/castle/burg'. Compare the standard river name
圣劳伦斯河 (Shèng Láolúnsī Hé, St. Lawrence River, Canada). The
罗伦斯 vs
劳伦斯 spelling varies between sources — both render 'Lawrence'.