Tears of Europa

In OTL, many things happend. In this ATL, two different things occured. The first and most important is that they advanced rapidly, making it to roughly 1600 technology by 1480. The second change is that when Pope Sixtus IV calls for a crusade against the Ottomans, they respond, throwing Europe into a full fledged war with the Ottomans, a war which eventually brings in other Muslims to the side of the Ottoman Empire.