Genucla is the name of an ancient fortress of the Getae, located on the riverbank of the Danube or on an island on the river. It is mentioned by Dio Cassius in his History of Rome (Historia Romana), in Book LI (51), chapter 26. The author describes the military campaign of Marcus Licinius Crassus to conquer Moesia. During this campaign he lays siege to the fortress Genucla, which was under the rule of Getaen king Zyraxes.
Dio Cassius said:
After this success he (Marcus Licinius Crassus) did not leave in piece the rest of the Getae, either, even though they had no connexion with Dapyx, but he marched upon Genucla, the most strongly defended fortress of the kingdom of Zyraxes, because he heard that the standards which the Bastarnae had taken from Gaius Antonius (Hybrida) near the city of the Istrians were there. His assault was made both by land and from the Ister (the city is built upon the river), and in a short time, though with much toil, despite the absence of Zyraxes, he took the place. The king, it seems, as soon as he heard of the Romans' approach, had set off with money to the Scythians to seek an alliance, and had not returned in time.