1636 : the Ottoman onslaught
(Book)

Armed with new weapons inspired by the time-displaced Americans of Grantville, the Turks--led by the young, dynamic, and ruthless Murad IV--are determined to do what they were unable to do in the universe the Americans came from: capture Vienna. And this time they won't have to face massive reinforcements from Austria's allies, because the only army Emperor Gustav Adolf can send to Austria is under the command of Mike Stearns, and it's already engaged in a desperate struggle for Bavaria. Or so they think. --,adapted from book jacket.