Strabo only mentioned Arethusa in his Geography, as a "very strong place" of Sampsigeramos and of his son Iamblikhos, "phylarchs" of the Emesene, who had allied themselves to Q. Caecilius Bassus against Caesar in 47 BC; the translators above cited have thought strange Strabo's not saying a word about Emesa.
Claims have been made that Emesa was founded by Seleucus I Nicator who established the Seleucid Empire upon the death of Alexander the Great.
However, according to Henri Seyrig, Emesa does not seem to have received any Greek colony and the authors' complete silence makes one think that it did not increase its visibility under the Seleucid kings.
According to Henri Seyrig, it even seems that Posidonius, to whom Strabo probably referred concerning the Emesenes' phylarchs' alliance with Q. Caecilius Bassus, regarded the Emesenes as a simple tribe, governed by its sheikhs, and still devoid of a real urban existence; according to Maamoun Abdulkarim, occupation of the citadel's tell does not confirm the existence of a real urban center in the plain before the Roman period and recent excavations have refuted the existence of vestiges preceding the Roman period under the actual town's outline, and the existence of an Emesene dynasty in the region, probably located in Arethusa, attests to the secondary nature of this area during the Hellenistic period.
Upon Pompey's submission of the Seleucid state of Syria to the Roman Republic in 64 BCE, the Emesene dynasty were confirmed in their rule as client kings of the Romans for aiding their troops in various wars.
At its greatest extent, the kingdom's boundaries extended from the Bekaa Valley in the west to the border with Palmyra in the east, and from Yabrud in the south to al-Rastan (Arethusa) in the north.
A marker at the Palmyrene's southwestern border was found in 1936 by Daniel Schlumberger at Qasr al-Hayr al-Gharbi, dating from the reign of Hadrian or one of his successors, which marked the boundary between Palmyrene and Emesene (Pliny the Elder asserted that both territories were contiguous); this boundary probably ran northwards to Khirbet al-Bilaas on Jabal al-Bilas where another marker, laid by Roman governor Silanus, has been found, 75 kilometres (47 mi) northwest of Palmyra, probably marking a boundary with the territory of Epiphania.
The kingdom of Sampsiceramus I, was the first of Rome's Arab clients on the desert fringes.

The city of Emesa grew to prominence after the new-found wealth of the Emesene dynasty, governed first by one of the sons of Sampsiceramus I, Iamblichus I who made it the kingdom's capital.
The Emesene proved their loyalty to Rome once more when they aided Gaius Julius Caesar in his siege of Alexandria in 48 BC, by sending him army detachments.
Subsequently, they became embroiled in the Roman Civil War between the rebelling Mark Antony and the pro-Caesar Octavian.
Iamblichus I took the side of Octavian, and so upon encouragement from Antony, Iamblichus's brother Alexio I usurped the throne and put Iamblichus I to death in 31 BCE.
Octavian's forces prevailed in the war, however, and as a result the kingdom's throne was reverted to Iamblichus II (the son of Iamblichus I) after Alexio I was executed for treason.
It was in 32 that Heliopolis and the Beqaa Valley came under the kingdom's control.
Relations with the Roman government grew closer when King Sohaemus inherited the kingship.
Under him, Emesa sent the Roman military a regular levy of archers and assisted them in their siege of Jerusalem in 70.
Sohaemus had died in 73.
According to Maurice Sartre, the dynasty was very likely deprived of its kingdom, which was annexed to the Roman province of Syria, between 72 and the date of the construction of the Tomb of Sampsigeramus (78–79).

 
Under the Romans, Emesa began to show attributes of a Greek city-state and traces of Roman town planning still remain.
Its transformation into a major city was completed under the reign of Emperor Antoninus Pius (138–161) when Emesa began to mint coins.
By the 3rd century, it grew prosperous and well integrated into the
Strabo only mentioned Arethusa in his Geography, as a "very strong place" of Sampsigeramos and of his son Iamblikhos, "phylarchs" of the Emesene, who had allied themselves to Q. Caecilius Bassus against Caesar in 47 BC; the translators above cited have thought strange Strabo's not saying a word about Emesa. Claims have been made that Emesa was founded by Seleucus I Nicator who established the Seleucid Empire upon the death of Alexander the Great. However, according to Henri Seyrig, Emesa does not seem to have received any Greek colony and the authors' complete silence makes one think that it did not increase its visibility under the Seleucid kings. According to Henri Seyrig, it even seems that Posidonius, to whom Strabo probably referred concerning the Emesenes' phylarchs' alliance with Q. Caecilius Bassus, regarded the Emesenes as a simple tribe, governed by its sheikhs, and still devoid of a real urban existence; according to Maamoun Abdulkarim, occupation of the citadel's tell does not confirm the existence of a real urban center in the plain before the Roman period and recent excavations have refuted the existence of vestiges preceding the Roman period under the actual town's outline, and the existence of an Emesene dynasty in the region, probably located in Arethusa, attests to the secondary nature of this area during the Hellenistic period. Upon Pompey's submission of the Seleucid state of Syria to the Roman Republic in 64 BCE, the Emesene dynasty were confirmed in their rule as client kings of the Romans for aiding their troops in various wars. At its greatest extent, the kingdom's boundaries extended from the Bekaa Valley in the west to the border with Palmyra in the east, and from Yabrud in the south to al-Rastan (Arethusa) in the north. A marker at the Palmyrene's southwestern border was found in 1936 by Daniel Schlumberger at Qasr al-Hayr al-Gharbi, dating from the reign of Hadrian or one of his successors, which marked the boundary between Palmyrene and Emesene (Pliny the Elder asserted that both territories were contiguous); this boundary probably ran northwards to Khirbet al-Bilaas on Jabal al-Bilas where another marker, laid by Roman governor Silanus, has been found, 75 kilometres (47 mi) northwest of Palmyra, probably marking a boundary with the territory of Epiphania. The kingdom of Sampsiceramus I, was the first of Rome's Arab clients on the desert fringes.
The city of Emesa grew to prominence after the new-found wealth of the Emesene dynasty, governed first by one of the sons of Sampsiceramus I, Iamblichus I who made it the kingdom's capital. The Emesene proved their loyalty to Rome once more when they aided Gaius Julius Caesar in his siege of Alexandria in 48 BC, by sending him army detachments. Subsequently, they became embroiled in the Roman Civil War between the rebelling Mark Antony and the pro-Caesar Octavian. Iamblichus I took the side of Octavian, and so upon encouragement from Antony, Iamblichus's brother Alexio I usurped the throne and put Iamblichus I to death in 31 BCE. Octavian's forces prevailed in the war, however, and as a result the kingdom's throne was reverted to Iamblichus II (the son of Iamblichus I) after Alexio I was executed for treason. It was in 32 that Heliopolis and the Beqaa Valley came under the kingdom's control. Relations with the Roman government grew closer when King Sohaemus inherited the kingship. Under him, Emesa sent the Roman military a regular levy of archers and assisted them in their siege of Jerusalem in 70. Sohaemus had died in 73. According to Maurice Sartre, the dynasty was very likely deprived of its kingdom, which was annexed to the Roman province of Syria, between 72 and the date of the construction of the Tomb of Sampsigeramus (78–79).
 
Under the Romans, Emesa began to show attributes of a Greek city-state and traces of Roman town planning still remain. Its transformation into a major city was completed under the reign of Emperor Antoninus Pius (138–161) when Emesa began to mint coins. By the 3rd century, it grew prosperous and well integrated into the
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