1450-1469 Gutenberg Invents Printing Press, Constantinople Falls

This twenty year period covers the reign of Henry VI whose kingship was usurped in 1461 by the Plantagenet Edward IV. In this period there was constant warfare in the world, but this period was glorious for the 1454 invention of the printing press by Gutenberg and the 1450 Italian invention of spectacles for short sightedness.

The 1425-1454 Wars in Lombardy were ongoing, and then came the 1453 Fall of Constantinople, the 1454-1466 Thirteen Years' War and the 1455-1485 Wars of the Roses.

The Turkish capture of Constantinople in 1453 was significant because it brought to an end the Byzantium Empire which, in 641, was all that remained of the former eastern Roman Empire. It was just a small area around Constantinople, exclusively Greek, which had reverted to its former Greek name - Byzantium. From 641 to 1453 the Byzantium emperors had ruled continuously.

In 1450 spectacles for short sightedness were invented in Italy and in 1454 Gutenberg invented the printing press (which later allowed humanism to spread throughout northern Europe). 

1410-1429 Venice at war with the Muslim Turks

This twenty year period covers the reign of Henry IV who died in 1413 and was succeeded by his son Henry V who died of dysentery in 1422 and was succeeded by his infant son Henry VI.

In this period there was constant warfare in the world, the most terrible war being the 1416 war between Venice and the Turks.

Venice was a thriving and very wealthy city, doing trade with all parts of the known world, and a Turkish victory would have thrown Europe even further into the Dark Ages than it was already.

Henry V's reign began and ended with bloody wars in France to claim the kingdom of France which he considered to be rightfully his in that he was married to Catherine, the daughter of the French King Charles VI.

In 1415 the Battle of Agincourt, followed by a systematic conquest of Normandy in 1417, a civilian massacre at Caen and the surrender of Rouen in 1419. 

In 1420 he entered Paris under the Treaty of Troyes -- by which Henry was to rule France -- but the Dauphin rejected the treaty. Then Henry died, leaving the succession to his infant son Henry VI.

As well as Henry V's wars, the 1409-1410 Teutonic-Polish War was coming to an end and then came the 1416 war between Venice and the Turks, the 1420-1436 Hussite Wars and the 1425-1454 Wars in Lombardy.

1670-1689 Ottoman Siege of Vienna, Two Williams

This twenty year period covers the reign of Charles II who died in 1685 and was succeeded by his brother James II who was deposed in 1688 and replaced in 1689 by his daughter Mary II and her Dutch Orange husband William III in what was known as the 'glorious revolution'. In this period there was constant warfare in the world, and Europe risked becoming Muslim when the Ottoman Turks lay siege to Vienna in 1683.

There was the Polish-Turkish War in 1671–1676, followed by the 1672–1678 Franco-Dutch War, the 1672–1674 Third Anglo-Dutch War, the 1672–1679 War between Brandenburg and Sweden, the 1675–1677 King Philip's War, the 1676–1681 Russo-Turkish War, the 1682–1699 War of the Holy League, the 1683 Siege of Vienna by the Ottoman Turks, Monmouth's Rebellion in 1685, the 1685-1689 Sino-Russian War, the 1686–1700 Russo-Turkish War, the 1687–1689 Crimean campaigns, the 1689–1697 King William's War in North America (part of the War of the Grand Alliance), the 1689–1691 Williamite war in Ireland and the 1689–1691 Jacobite Rising in Scotland.

The Siege of Vienna by the Ottoman Turks in 1683 was of particular concern because if the Holy League had not joined together to fight the Turks it is likely that the whole of Europe would have become Islamic.

The deposing of the Catholic James II by the Protestant William of Orange in 1688 and a sad event in our history. It started the Jacobite movement in Scotland and Europe and James II never abandoned hopes for a Stuart restoration. His son, Charles Edward Stuart, born in Rome in 1720, carried on the struggle as Bonnie Prince Charlie.

Because of constant warfare there were no great inventions or discoveries during this twenty year period, but William Penn did stand out for presenting a vision of harmony in the new world. He was granted the Charter of Pennsylvania in 1681 and founded Philadelphia in 1682 with migrants he had previously attracted during his travels through war-ravaged Europe.