1187 can refer either to the integer that follows 1186 and precedes 1188, or to the calendar year 1187 CE. As a numeral it appears in arithmetic, coding, and indexing; as a historical year it marks a major turning point in the history of the Crusades and in medieval Near Eastern politics.

Mathematical and notational properties

As an integer, 1187 is an odd number and is prime: it has no positive divisors other than 1 and itself. Common representations include the Roman numeral MCLXXXVII, binary 10010100011, and hexadecimal 0x4A3. Because it is prime, 1187 is used in contexts that rely on prime numbers, for example cryptographic keys or mathematical examples, but it has no especially distinctive arithmetic properties beyond being a four‑digit prime.

Year 1187 — overview and significance

The year 1187 CE is best known for events in the eastern Mediterranean that reshaped Christian–Muslim relations. The Muslim leader Saladin (Ṣalāḥ al‑Dīn) defeated the Crusader armies at the Battle of Hattin and soon after captured Jerusalem and other Crusader strongholds. These developments ended several decades of Christian control over Jerusalem and precipitated a military and political reaction in Western Europe.

Notable events of 1187

  • Battle of Hattin (July 1187): The forces led by Saladin defeated the main Crusader army, weakening the Latin Kingdom of Jerusalem.
  • Capture of Jerusalem (October 1187): Following a campaign across the Levant, Saladin took Jerusalem, a symbolic and strategic loss for the Crusader states.
  • Aftermath: The fall of Jerusalem galvanized European rulers and the papacy to organize a new expedition, contributing directly to the launch of the Third Crusade (commencing a few years later).

The consequences of 1187 were long lasting: military, diplomatic, and cultural engagements between Europe and the Islamic world intensified. Western monarchs, including figures such as Richard I of England, Philip II of France and Frederick I (Barbarossa) of the Holy Roman Empire, later became prominent leaders of the campaign known as the Third Crusade.

Beyond its medieval importance, 1187 as a number serves in everyday modern uses—cataloguing, addresses, model numbers and examples in mathematical discussion. Its historical resonance, however, is what most often gives the numeral a place in popular memory: the year is frequently cited in discussions of the Crusades, medieval diplomacy and the shifting balance of power in the eastern Mediterranean.