The Boston Massacre became an important symbol for radicals who used the incident to build popular opposition to British rule. For thirteen years after the incident, Boston observed March 5, the anniversary of the incident, as a day of public mourning. Artists continued to redraw, repaint, and reinterpret the Boston Massacre long after it occurred. This engraving based on a painting by Alonzo Chappel was published in 1868. While the artist still omitted Crispus Attucks, a black sailor who was one of those killed in the Massacre, it showed the chaos of the confrontation and captured the horror of soldiers shooting down unarmed citizens.