Short answers, pulled from the story.
Historical reenactment is an educational or recreational activity in which enthusiasts and amateur hobbyists dress in period-accurate clothing and recreate aspects of past events or eras. Participants are mostly amateurs, though military personnel and professional historians also take part. Ages range from young children to the elderly.
The first known reenactment on record took place in 1638, attributed to Lord James Dunn of Coniston, and featured dozens of costumed performers in a staged battle in London.
The Eglinton Tournament of 1839 was a large-scale reenactment of a medieval joust and revel, organized by Archibald Montgomerie, the 13th Earl of Eglinton, and held on a meadow at a loop in the Lugton Water in Scotland. It drew one hundred thousand spectators and featured thirteen knights on horseback. Admission was free.
A farb is a reenactor who spends relatively little time or money achieving authenticity in uniforms, accessories, or period behavior. The word appears to date to the early American Civil War centennial reenactments around 1960 or 1961, and its precise origin is disputed. One account traces it to George Gorman of the 2nd North Carolina, who spread the term after the Centennial Manassas Reenactment in 1961.
A 1920 reenactment of the 1917 Storming of the Winter Palace, staged on the third anniversary of the event, directly inspired scenes in Eisenstein's film October: Ten Days That Shook the World.
Historians have argued that reenactment cannot truly recover the past, because modern participants inevitably filter all experience through a contemporary lens. Critics of American Civil War reenactment have specifically warned that a focus on costume accuracy can push the war's causes, including the end of slavery, to the margins. Scholars have also noted that reenactors in the United States are overwhelmingly white, and that at the 150th Gettysburg anniversary in 2013 only five black reenactors were present.