Carl Fredrik Aagard was a 19th century Danish painter, apparently best known for his views of Italy’s Amalfi Coast and Lake Como regions.
I can find little else about him, and only this one repository of images on Wikimedia Commons, but that, and the tantalizing similarity of a couple of his paintings to those of Peder Mønstead, is enough to make him interesting.
[Addendum: See this post’s Comments for bio information courtesy of reader Ælle.]