Complex sentence: Arneson's role-playing game design work grew from his interest in wargames when his parents bought him the board wargame "Gettysburg" by Avalon Hill in the early 1960s.
Split into simpler sentences: Arneson's role-playing game design work grew from his interest in wargames. His parents bought him the board wargame "Gettysburg" by Avalon Hill in the early 1960s.