My Milan > Italy Game in 1538.
Annexed Tuscany when they joined a war against me early on, vassalized Genoa and Ferrara in a war where my ally, the Papal States, refused to join. Vassalized the Papal States in a war immediately after that one. Castille took Ancona, but I managed to beat them in a war and force them to release Urbino, which I subsequently forger claims on and enforced a personal union. Inherited them about 15 years before Rome cored in 1499, and formed Italy. Vassalized either peacefully of through war all the Italian minors, and now I have all my cores except Friuli (owned by Aquileia, my vassal) and Istria (Austrian).
Unfortunately, France has become one of the strongest countries I've ever seen (their army is about the size of mine and Austria's combined), but I've stayed on good terms with them. Apart from the time when they got a stupid mission to "restore the Holy See" (meaning they had to take Rome), and I was forced to load it up as France and cancel the mission.
I have colonized a few islands in the Antilles and a chunk of Brazil, the only other colonizer thus far being Portugal. Russia formed, Britain will be forming in 20 years, and Scandinavia will also form if they can take Oslo from Austria. Netherlands and Spain both almost formed until their dreams were dashed by France.
Hungary got some bad religious revolts, to the point where they had a bunch of random provinces defect to the Papal States and Aquileia (defeder of the Protestant faith).