One of the greatest and most important battles of all time, the Ottoman Turkish siege of Constantinople [now Istanbul] saw the Turks use heavy siege artillery for the very first time in history to break through the enormous city walls that had held off attackers for more than a thousand years, bringing to an end the last remains of the old Roman Empire.

Watch the detailed map animation, showing the formations, attacks and development of the siege.

Listen to the audio commentary and follow the full course of the assault.

Read the historical account of the background, the course of the action and the aftermath to Constantinople.

View the gallery, which includes artworks of the combatants and weaponry. Locator maps show you where the battle happened and charts give you a breakdown of the numbers of forces on each side.

Try out your knowledge with the battle quiz. Do you know what a Janissary or a trebuchet is, what prompted the attack, or where the crossbowmen fighting at Constantinople came from?

This is history at hand: one of the major events in world history on your device.