Continuing our look at Civil War sites in St. Augustine, Florida, this is the main entrance or sally port to the historic Castillo de San Marcos.
Now a national monument, the Castillo is the oldest masonry fort in the continental United States. Construction on the Spanish fortress began in 1672 and it took decades to complete. St. Augustine was already 107 years old when work started on the Castillo.
The old fort withstood massive English sieges during the 18th century, but never fell. The unique coquina rock from which it was constructed absorbed the British cannon shot without shattering and even a bombardment that lasted for nearly 30 days failed to breach the walls.
The fort was held by a Ordnance Sergeant at the beginning of the Civil War, but was seized by state militia troops on January 7, 1861, as Florida was still considering the issue of secession.
The Confederate troops held the fort until the spring of 1862, when they evacuated St. Augustine as Union ships approached the historic city. Two companies of troops were occupying the old fort at the time of the withdrawal.
It is interesting to note that despite the obvious antiquity of the fort (it was nearly 200 years old at the time), one of the Union naval officers described it as one of two "strong" positions that had been returned to Union hands.
It has long been thought that because of its age, the Castillo would not have been able to withstand an attack, but this is questionable. In fact, it might have proved a tough nut to crack. The walls of the old Spanish fortress were massive and the Castillo was designed to make an infantry attack extremely difficult. In fact, the fort withstood a 52 day assault at one point and the attacking infantry got nowhere near the walls.
The inlet to the harbor and Matanzas Bay was shallow and extremley difficult for warships to navigate, as the Union navy found out when it tried to send in a ship to to find out if St. Augustine had been evacuated. The vessel couldn't make it in and had to send in boat parties and then contrary winds caused all kinds of nightmares for the effort. In other words, Union warships would have been positioned miles away in any attempt to bombard the works.
Anastasia Island separates Matanzas Bay from the Atlantic and Union forces could have placed artillery there, but it would not have been easy. Shallows called "conch island" are offshore of Anastasia and would have obstructed efforts to land artillery. In addition, Anastasia Island is within 2 miles of the Castillo. Placing guns at that range would have been created a turkey shoot for the heavy artillery in the fort's water battery.
To the north, vast salt marshes stretch away to the horizon and to the west, the San Sebastian River forms a natural moat around the city. In other words, it would have been very difficult to move enough artillery into position to reduce the fort.
Our series on St. Augustine will continue. Until then, you can read more by visiting www.exploresouthernhistory.com and looking for the St. Augustine heading.