Shaizar or Shayzar (Arabic: شيزر; in modern Arabic Saijar; Hellenistic name: Larissa in Syria, Λάρισσα εν Συρία in Greek) is a town in northern Syria, administratively part of the Hama Governorate, located northwest of Hama.

Shaizar is located at a strategically vital crossing point on the Orontes River, 28 km to the northwest of Hama.

Diodorus Siculus (first century BC) records local legends attributing the establishment of the town by one of Alexander's cavalry regiments originating from Thessaly.

[citation needed] A Fatimid castle was standing at Shaizar by the time the Byzantines recaptured the town.

The interaction between the Crusader states and the Banu Munqidh rulers of Shaizar consisted of a series of wars and alliances.

[citation needed] The Munqidhites controlled territory east of Shaizar, across the al-Ansariyah mountains to the Mediterranean coast, from the coastal cities of Latakia in the north to Tortosa in the south.

Tancred, Baldwin I of Jerusalem, and Bertrand of Tripoli besieged the city during the battle of Shaizar of 1111 for two weeks, but returned home when the army of Mawdud of Mosul cut off their access to food and water.

[citation needed] When Ridwan of Aleppo died in 1113, Shaizar was inundated by many of his Assassin supporters that were expelled from the city by his son Alp Arslan al-Akras.

When Baldwin II of Jerusalem was taken captive by the Artuqid Belek Ghazi outside Edessa in 1123, he was held at Shaizar until his release the next year.

In April 1138, the Byzantine army led the siege of Shaizar, but Raymond and Joscelin II of Edessa did not assist the emperor.

The emirate lasted until the enormous earthquake of 1157, during which the citadel collapsed, killing almost the entire family, who had assembled there to celebrate a circumcision.

He was the nephew and potential successor of the emir of Shaizar, but was exiled in 1131 and spent the rest of his life serving other leaders.

He was a courtier to the Burids, Zengids, and Ayyubids in Damascus, serving the Zengi, Nur ad-Din, and Saladin over a period of almost fifty years.

He traveled extensively in Arab lands, visiting Egypt, Syria, Palestine and along the Tigris River, and went on pilgrimage to Mecca.

The citadel (castle) was declared a national monument in 1958 and the last inhabitants were evacuated to prevent archaeological damage.