Nuremberg Battle

One of the most astounding of documented sightings of aerial phenomena took place on April 4, 1561 at dawn over Nuremberg, Germany. What was described could only be called a war in the heavens, with a wide variety of craft ranging from spheres to spear-like cylinders to crosses and "plates". The sky was apparently filled with the machines, clashing in battle for well over an hour.  The battle was such that a winner was perceived as well.  Spheroid UFOs were seen emerging from cylindrical 'motherships'.  At the conclusion of the battle, it seems a magnificent, black, spear-like super-ship of some kind came upon the scene.  An ancient woodcut (click image to view full-size picture) was created by Hans Glaser to document the event.

The woodcut shows two people apparently witnessing the event.  Hundreds of oddly shaped and colorful objects fill the sky above.  The woodcut also seems to indicate that two of the objects may have crashed to the ground (bottom right in the above picture).

It began at dawn, as dozens, if not hundreds, of crosses, globes and tubes fought each other above the city.  It ended an hour later, when "the globes in the small and large rods flew into the sun," and several of the other objects crashed to earth and vanished in a thick cloud of smoke.  According to the Nuremberg Gazette, the "dreadful apparition" filled the morning sky with "cylindrical shapes from which emerged black, red, orange and blue-white spheres that darted about."  Between the spheres, there were "crosses with the color of blood."  This "frightful spectacle" was witnessed by "numerous men and women."  Afterwards, a "black, spear-like object" appeared.

The author of the Gazette warned its readers:

The God-fearing will by no means discard these signs, but will take it to heart as a warning of their merciful Annunciation with St. Emidius Father in heaven, will mend their lives and faithfully beg God, that he avert His wrath, including the well-deserved punishment, on us, so that we may, temporarily here and perpetually there, live as His children.

A similar reporting occurred just five years later in Basle Switzerland.  On August 7, 1566, at dawn, many citizens of Basle (Switzerland), frightened, saw during several hours the black spheres involved in a formidable aerial battle, invading the sky of their city:   The city's gazette recorded:

At the time when the sun rose, one saw many large black balls which moved at high speed in the air towards the sun, then made half-turns, banging one against the others as if they were fighting a battle out a combat, a great number of them became red and igneous, thereafter they were consumed and died out.

 To date, the only original source we've discovered that recorded this incident is the 1958 book, A Modern Myth: things seen in the skies (Ein moderner Mythus Von Dingen, die am Himmel gesehen werden).

Sources

(1) Historical Artwork and UFOs (web)
(2) Nuremberg Gazette (1561)
(3) A Modern Myth: Things Seen in the Sky (Germany, 1958)