The Changing of the Guard: A Reenactment of a Daily Duty in Colonial Spanish St. Augustine. Wearing the distinctive blue coats of the 18th century Spanish soldier, members of San Agustin Garrison march into place for the Changing of the Guard.   Step back in time and imagine a typical day in 1740 St. Augustine where soldiers are guarding the little colonial city.  They are dismissed for the night, but not before their replacements arrive and are ready to take over the duty of guarding Government House, the home of the Spanish Governor and the seat of power.   This reenactment is one of the opening events of  the ten-day Romanza Festivale and occurs in front of Government House on the Plaza.