Antiochus gives up all his conquests of the Fourth Syrian War in the peace that settles it, except the city of Seleucia-in-Pieria.

Ptolemy's new army (numbering seventy-five thousand) meets the Seleucid forces (sixty-eight thousand strong) near Raphia in southern Palestine in the spring of 217, however, and with the help of the Egyptian phalanx, Ptolemy is victorious.

The battle is notable for the fact that large numbers of native Egyptian soldiers have for the first time fought alongside the Macedonian and Greek contingents.

The Egyptian king, although holding the initiative, negotiates a peace on Sosibius' advice, and the Seleucid army withdraws from Coele Syria.

Ptolemy after his victory at Raphia marries his sister, Arsinoe.

Philip of Macedon, having expelled the Aetolians from the Peloponnese, marches into Aetolia, sacking the federal capital of Thermum.

He makes peace in 217 with Aetolia.

Maximus, commanding the Roman forces in the south, harasses Hannibal with delaying tactics, earning for himself the nickname “Cunctator” (delayer), first employing these tactics—harassing Hannibal's army but not joining battle—after the Roman defeat at Lake Trasimene.

The cautious Maximus is overshadowed, however, by the more aggressive Marcus Minucius Rufus.

Consuls Lucius Aemilius Paullus and Caius Terentius Varro, more impatient than Fabius Maximus, lose four legions on August 2, 216 in a trap laid by the outnumbered Hannibal, a double envelopment, at Cannae in southeastern Italy.

The younger Publius Cornelius Scipio, serving as a military tribune, helps rally survivors of the debacle, which cost the Romans nearly sixty thousand soldiers to Hannibal’s eight thousand.

Livy writes "it is said that forty-five thousand five hundred foot soldiers and twenty-seven hundred horsemen were slain in almost equal proportion of citizens and allies".

He also reports that three thousand Roman and allied infantry and fifteen hundred Roman and allied cavalry were taken prisoner by the Carthaginians.

Although Livy does not cite his source by name, it is likely to have been Quintus Fabius Pictor, a Roman historian who fought in and wrote on the Second Punic War.

(A member of this era’s flourishing Fabii, Pictor writes a history of Rome in Greek—lost to us—that traces the beginnings of Rome to Aeneas.)

Marcus Claudius Marcellus had gained the most prestigious award a Roman general could earn, the spolia opima, for killing the Gallic military leader and king Viridomarus in hand-to-hand combat in 222 BCE at the battle of Clastidium during the Gallic War of 225 BCE.

He is noted for having saved the life of his brother, Otacilius, when the two were surrounded by enemy soldiers in Italy.

Elected praetor in in 216 BCE, the third year of the Second Punic War, Marcellus is selected to commander the army in Sicily.

As Marcellus and his men prepare to ship to Sicily, his army is recalled to Rome owing to the devastating losses at Cannae, considered to be one of the worst disasters in the long history of Rome By the orders of the Senate, Marcellus is forced to dispatch fifteen hundred of his men to Rome to protect the city after the terrible defeat by Hannibal of Carthage.

With his remaining army, along with remnants of the army from Cannae, (who are considered to have been disgraced by the defeat and by surviving it), Marcellus camps near Suessula, a city in the region Campania of Southern Italy.

At this point, part of the Carthaginian army begins to make a move for the city of Nola.

Marcellus repels the attacks and manages to keep the city from Hannibal’s grasp.

Rome has lost one-fifth (one hundred and fifty thousand) of the entire population of citizens over seventeen years of age within just three campaign seasons (twenty months).

The bravest Roman armies in the peninsula have been destroyed, the few remnants severely demoralized, and the only remaining consul (Varro) completely discredited.

In the face of this appalling catastrophe, the desperate Romans resort to human sacrifice, twice burying people alive at the Forum of Rome and abandoning an oversized baby in the Adriatic Sea.

As Hannibal had hoped, the Samnites and many other peoples of southern Italy now abandon Rome.

The Hellenistic southern provinces of Arpi, Salapia, Herdonia, Uzentum, including the cities of Capua and Tarentum (two of the largest city-states in Italy) all revoke their allegiance to Rome and pledge their loyalty to Hannibal.

Rome, refusing to accept defeat, resumes Fabius' brilliant strategy of delay and harassment, frustrating Hannibal from delivering a mortal blow and beginning to wear down his strength.

Aratus now begins to lead the Achaean League in resisting Philip's anti-Roman policy and his interference in Messene.

The ambitious Philip V of Macedon, now popular throughout much of Greece following his decisive actions in the so-called War of the Allies (also the Social War of 219—217), looks to extend his empire while Rome is preoccupied with fighting Carthage in the Second Punic War.

In an attempt to stem the tide of Roman expansion, sets out to attack Rome's client states in neighboring Illyria.

He confirms his purpose in 215 by making an alliance against Rome with Hannibal, the Carthaginian general who is invading Italy and is interested to protect supply lines from North Africa.

Philip, currently the most powerful ruler in the Balkans, thus initiates ten years of inconclusive warfare against Rome (First Macedonian War, 215-205).

Rome responds by supporting Philip's many enemies in the Balkans as they fight the war, which expands Roman interests into the Balkans.