Accordingly he ordered hostages to be given, and fixed the tribute which Britain was to pay annually to the Roman People, at the same time strictly forbidding Cassivellaunus to molest Mandubracius or the Trinovantes.
On receiving the hostages, he led back the army to the sea, where he found the ships repaired....
Cicero to Atticus: “I received a letter on the 26th of September from my brother and from Cæsar, dated from the nearest coasts of Britain on the 29th of August. Britain done with – hostages taken – no booty – a tribute, however, imposed; they were on the point of bringing back the army.” (‘Letters to Atticus’ Book IV no18)
.... When they were launched, he arranged to take the army back in two trips, as he had a large number of prisoners and some ships had been destroyed by the storm.”
‘The Gallic War’ Book V Chapters 22 & 23
The first trip was made satisfactorily. The ships, having unloaded, were joined by sixty new ships – built by Labienus – for the return voyage to Britain. Yet again, the weather conspired against Caesar, and most of the empty vessels were driven back:
“Caesar waited for them a considerable time in vain; and then, for fear the lateness of the season (just before the equinox) should prevent his sailing, he was obliged to pack the troops rather closely. A dead calm followed, and unmooring at the beginning of the second watch [about 9pm], he reached land at dawn and brought all the ships safe ashore.”
‘The Gallic War’ Book V Chapter 23