S1: It was in 264 B.C. that the great struggle between Rome and Carthage, the Punic Wars began.
S6: But the Romans, with extraordinary energy, set themselves to out build the Carthaginians.
P: It gradually developed into a struggle for the possession of Sicily.
Q: The advantage of the sea was at first with the Carthaginians.
R: The First Punic War began in that year about the pirates of Messina.
S: They had great fighting ships of what was hitherto an unheard-of size.
The proper sequence should be: