When South Carolina seceded, this flag flew over the customs house in
Charleston and then in various cities around the state as a
symbol of secession itself. This flag was NOT the national flag of an independent South Carolina. It predates the secession of all the states and of the Confederacy. As such it is an expression of public sentiment at the time.
A newspaper account of the events on the day of Secession states that some Charleston ladies sewed the first flag which did not include the crescent and that it was first flown at the top of a pine tree which had been stripped by slaves. Before the battle of Fort Moultrie (then Fort Sullivan) a rich man in Charleston bought uniforms for the troops and put the crescent on their helmets.
The crescent, a South Carolina symbol since revolutionary times, is upside down
which is said to be a sign of distress. The star is said to
symbolize Southern unity. It then became a South Carolinian Navy flag.