Alexander was now focused on India. In the spring of 327 BC, Alexander and his army marched into India invading Punjab. The greatest of Alexander's battles in India was at the river Hydaspes, against king Porus, one of the most powerful Indian rulers. In the summer of 326 BC, Alexander's army crossed the heavily defended river during a violent thunderstorm to meet Porus' forces. The Indians were defeated in a fierce battle, even though they fought with elephants, which the Macedonians had never seen before. Porus was captured and like the other local rulers he had defeated, Alexander allowed him to continue to govern his territory. In this battle Alexander's horse Bucephalus was wounded and died. Alexander had ridden Bucephalus into every one of his battles in Europe and Asia, so when it died he was grief-stricken. He founded a city which he named Bucephalia, in his horse's name.