there is no such thing as greater syria.

the SSNP or syrian socialist party have a theory that modern day Lebanon, israel, palestine, parts of rurkey and Jordan and even Cyprus were once a part of what they call greater syria.

After World War I, the French received a colonial mandate over Greater Syria, which became the countries of Syria and Lebanon.

Syria gained its independence in April 1946 from France. However, before that the region of "Greater Syria" (Bilad al-Sham or the countries of the north) consisted of the region of the current states of Syria, Lebanon, Jordan, and Israel/Palestine and was an administrative region of the Ottoman Empire, as well as many former empires such as the Abbasids, Umayyads, and even the Romans and Greeks before that.

A British built telegraph connected Aleppo, Beirut, and Damascus

ISOL is a another acronym for ISIS. ISIS/ISOL is the Islamic State of Iraq and Sham ("Greater Syria"). The terrorist organization now trying to take over Syria and Iraq.

There are other meanings for ISOL but this is the most topical one.