Proteus Gowanus is like a gallery, curiosity shop and library in one–a place you should visit at least once in your Brooklyn life, and this Saturday is a prime time to explore their work. Each year they pick a theme for their group art shows, and this year “Battle” was the inspiration for three exhibitions. The final one commemorates and contextualizes The Battle of Brooklyn, the first battle we ever fought as a nation (and lost). Its culminating moments occurred just steps from the gallery, where artists like Duke Riley and Robert Gould, along with scholars, urban planners and writers, have joined forces to revive the historical images and lore. Battle Ground opens Saturday at 7pm, with treats from Runner and Stone.