This is a photostream from a bloke in Sydney on flickr. Much of it is irrelevant but he has some beautiful images from a book published in the 1880's, largely from the Renaissance.
"A listing of over 5000 websites describing holdings of manuscripts, archives, rare books, historical photographs, and other primary sources for the research scholar. All links have been tested for correctness and appropriateness."
An excellent collection of public domain ebooks run out of the University of Adelaide, focussing on literature, philosophy, science and the queen of all subjects, History. She deserves a capital.
A vast collection of source sites and resources on the Classical world, including Greek and Latin texts. They're even working on a translation of Harry Potter into Greek - maybe they can send JK Rowling some correct Latin terms instead of the mangled gibberish she puts in the books...
You'll need to be able to read German and Classical Latin, but once those minor hurdles are overcome this is a rich collection of primary sources on early German history. I only had a brief peek but it seems to focus on ancient & medieval Germany. I guess they're written in Latin as it was the lingua franca of Europe at the time. They're organised into books with chapters and indices so it's unlikely they were written in Roman times (or at least it seems so to me).
Actually, the MGH is a collection of sources mainly for medieval Germany (of course including areas that are not German today), initially started with the intent to create a complete edited version of sources for the middle ages. They are in fact organised by type, like legal documents, letters, chronicles, etc., whereas chronicles are also organised by author.
It's an invaluable reference for everyone doing work in medieval history. By the way, the link you saved doesn't work, I'd instead use this one: http://www.mgh.de/dmgh/