Geographical has an article about Oculus Mundi, the online home of the Sunderland Collection, a private collection of 13th- to 19th-century maps amassed over the years by its eponymous founder, Neil Sunderland, that sat in storage before the decision to digitize it and make it more accessible. I’m glad the article is here to introduce us to the collection, because the Oculus Mundi site is a bit over-designed and can be a challenge to navigate, especially at first. But making private map collections digitally accessible is always a good and laudatory thing, and in this case there’s plenty of good stuff to browse: try starting with this link.