When did the angel archetype change from masculine to feminine?

Throughout the Bible, angels typically appear as men or a masculine form. They're often described as warriors, engaging in battle. (Source ) However, in modern, generally Western (or at least American) culture, angels are thought of as feminine figures, often portrayed by women (or Victoria Secret models). (Source ) **When (about) did this change occur?** --- I realize this may not be a very well-developed question (please, feel free to modify/enhance it), but I think I'm on to something here - even if it is merely a curiosity. I get the feeling that one of the reasons for angels being thought as feminine has something to do with the New Age movement and their concept (and often worship of) Guardian Angels, but it's just a gut feeling or sorts.