De Bello Gallico 5.18

5.18.1Caesar cognitō cōnsiliō eōrum ad flūmen Tamesim in fīnēs Cassivellaunī exercitum dūxit;

Learning their plan, Caesar led his army to the river Thames, into the territory of Cassivellaunus;

5.18.1quod flūmen ūnō omnīnō locō pedibus, atque hoc aegrē, trānsīrī potest.

this river can be crossed on foot at only one place, and that with difficulty.

Note. atque hōc aegrē: 'and that with difficulty'. hōc refers to the crossing.

5.18.2Eō cum vēnisset, animum advertit ad alteram flūminis rīpam magnās esse cōpiās hostium īnstrūctās;

When he arrived there, he noticed that large enemy forces were drawn up on the other bank;

5.18.3rīpa autem erat acūtīs sudibus praefīxīs mūnīta, eiusdemque generis sub aquā dēfīxae sudēs flūmine tegēbantur.

the bank was protected by sharp stakes fixed along the front, and stakes of the same kind were driven in under the water and hidden by the river.

5.18.4Hīs rēbus cognitīs ā captīvīs perfugīsque Caesar praemissō equitātū cōnfestim legiōnēs subsequī iussit.

Learning this from prisoners and deserters, Caesar sent the cavalry ahead and ordered the legions to follow immediately.

5.18.5Sed eā celeritāte atque eō impetū mīlitēs iērunt, cum capite sōlō ex aquā exstārent, ut hostēs impetum legiōnum atque equitum sustinēre nōn possent rīpāsque dīmitterent ac sē fugae mandārent.

But the soldiers went with such speed and such force, though only their heads were above the water, that the enemy could not withstand the attack of the legions and the cavalry, and abandoned the banks and took to flight.

Note. cum capite sōlō ex aquā exstārent: 'though they stood out of the water with only their heads'; cum here means 'although'.