Sandman, "August" issue (originally #30), features a dark!Caesar story about Octavian. It’s part of the “Distant Mirrors” series, which also covers the French Revolution, Emperor Norton, and Haroun al-Raschid; these stories and others were later collected in the paperbackFables and Reflections.
Immodest Acts: The Life of a Lesbian Nun in Renaissance Italy by Judith Brown. (Actually extends well beyond the Renaissance into the 17th century.) “The lesbian part is the most eye-catching, but it's definitely not the nuttiest part of the story- the nun in question only got caught because she started proclaiming that Jesus was visiting her in visions, and that she was married to him on the astral plane in Heaven.”
Below Stairs by Margaret Powell, which inspired the series Upstairs, Downstairs and Downton Abbey. “Powell worked as a housemaid in the 1920s, and wrote several scathing memoirs about the experience. This is the first one.”