The ancient fortress of Castle San Marco, the name of which has been improperly changed to Fort Marion, is considered one of the most attractive and interesting objects in St. Augustine. It was constructed in the style of the strong castles in Europe during the Middle Ages, after the design of military engineering employed by Vauban. In 1762 it was called St. John's Fort, or San Juan de Piños, afterward San Marco, which name it retained until the change of flags in 1821, when it received the title of Fort Marion, in honor of General Marion, of Revolutionary fame. Its form is that of a quadrilateral, or trapezium, with bastions at each corner, the wall being twenty-one feet in height. Its extreme age, together with the durability of material employed, would be a subject of more interest to ancient architects, could they return, than to any of the present generation. The battery is the boulevard of the city, where we can come and listen to the sea beating its great heart against the rocks, and see the snowy sails that glide so swiftly out to the solemn seas, while the white clouds float gracefully in their blue vault over our heads, like doves through the air, as the clear waters from the inlet flash in the bright sunlight, like burnished armor for a gala-day parade, and a pensiveness steals over our senses, which makes all earthly scenes vanish, like shadows in the distance at breaking of day. We also find this a favored place for receiving serious impressions--this structure, formed by long-forgotten hands, which was a fortress of strength for the defenseless, a prison for treacherous captives, where they could pine and die far from the sound of human sympathy, with the gates of mercy forever sealed to them. The mind embalms pleasant memories from this peculiar spot, when the skies are bright, bursting upon our vision like that day of which we read, whose "morning will dawn without clouds." This structure was commenced in 1565, by the Spaniards, as a defense against the Indians. In 1732 Don Manuel Montiano, being appointed Governor of Florida, made application to the Captain General of Cuba for means to strengthen the fort, also more artillerymen, which were granted, the work being done under the direction of Don Antonio de Arredonda, a competent engineering official. In response to his request, two hundred convicts from Mexico being furnished him, six casemates were finished, of which there are eighteen in all, the remainder having been completed in 1756. The impress of two eighteen-pound shot, low down on the eastern curtain, are now to be seen, [Illustration: LAND APPROACH TO FORT MARION.]