Caesar went on, after the the conference of Luca to reduce the whole of Gaul to submission in the course of three campaigns - justified by initial aggression from the barbarians.
The two following years were occupied with expeditions and campaigns of an experimental kind. In 55 BC a fresh invasion of Germans across the Rhine was completely shattered in the neighbourhood of modern Koblenz and the victory was followed by a great raid over the river into German territory, which made Caesar decide that the Rhine should remain the boundary.
Gaul conquered and the Germans crushed, Caesar turned his attention to Britain. In 55 BC he led his first expedition to Britain, a land so far known only by the reports of traders.
The following year, 54 BC, Caesar led his second expedition, and reduced the south-east of the island to submission. But he decided that real conquest was not worth undertaking.
During that winter and the following year 53 BC, the year of the disaster of Carrhae, Caesar was kept occupied with various revolts in north-eastern Gaul.