It was near the Ides of Sextilis, meaning the campaign season was drawing to a close and in consequence, Caesar picked up the pace of the operations. Portus Cale had been taken by a confederation of the Gallaeci Bracari and the Gallaeci Lucenses, who normally warred on each other but were now united in their common hatred of Rome, and slaughtered all the Roman citizens who did not flee. By the time we arrived at the walls, Caesar’s practice with the last few towns and cities was well known, so there was never any question as far as the enemy was concerned whether or not he would offer terms. To delay the inevitable, they burned the bridge across the Douro, which at that time was made of wood, and it was here that Caesar made a demonstration of his abilities as an engineer. To be fair, it was a demonstration of his ability at design, since it was the praefectifabrorum who had to actually put his design into use. It was not as large or ambitious as his later bridge over the Rhenus (Rhine); still it clearly awed the Gallaeci, who stood watching helplessly from a distance as in the space of a day, a pontoon bridge was built over the river using confiscated boats. On top of the boats, planking was laid of a sufficient strength that a Legion and an ala of cavalry could march across to set up a defensive camp protecting the selected site. The main problem of building a more permanent bridge, besides the Gallaeci trying to destroy it, stemmed from the banks of the Douro rising up steeply from the river, with very little flat and stable riverbank on which to build. Much later a bridge of stone was erected, but at the time our orders were to erect one that was sufficient to allow the Legions, along with their baggage trains and artillery to pass over, just not one that would take more than a few days to build. One challenge was finding timber suitable for using as the piers to hold the bridge up, but within a half day of our arrival, Caesar had seen what needed to be done. Simultaneously ordering the construction of the pontoon bridge, he also sent several Cohorts and wagons out to scour the area for wood of sufficient size for a more permanent structure. It was found a half-day’s march from our location, and it was a good thing that Caesar did not tarry, because fairly quickly the Gallaeci succeeded in destroying the pontoon bridge, sending several fire rafts downstream to run into the boats holding the bridge up. This effectively cut the 9th off on the far bank, not as much of a military threat as it meant that the three day’s rations they marched over with would have to suffice. The 7th and 10th were left on the south side of the river as a labor force, while the artillery was set up on the high bank of the Douro to provide covering fire and to keep the Gallaeci from getting any more ideas. By dawn on the fourth day, the bridge was finished, and even from a distance it was easy to read the despair of the mounted men who were our constant shadows while we worked and the 9th watched. They made no attempt to attack the 9th in its camp, which was probably a mistake, though it was one that suited us perfectly fine. It was clear to us that they thought that they had earned enough of a reprieve that it would allow time for the Gallaeci Lucenses to send fresh reinforcements down from the north to help them stop us, but the problem for them was that Caesar knew it as well. However slight the delay was, we still had to be quick about taking the town, and it was here that Caesar made another one of his decisions that is a demonstration of his tactical brilliance. Leaving the 7th to besiege the town, he continued the march north with the 9th and 10th to confront the Lucenses separately, trusting the 7th to take care of the Bracari. This was totally unexpected by both parts of the enemy force, and it was no more than two days after we crossed the Douro that our scouts came galloping back to the main column to report that they had spotted the advance scouts of the Lucenses column. Approaching to within sight of their own advance party, for the better part of a third of a watch the two sides sat on opposing hills no more than two miles away while the Lucenses scouts and what we presumed were their leaders talked over what to do. Not that we were idle; the cornu and bucina were blaring out orders that told us to array along the top of the hill in a triplexacies, although we still were waiting for the 9th to arrive in full since they were marching drag. But as usual, Caesar knew what he was doing. Just the sight of our one Legion making preparation for battle was enough to convince the Lucenses that they needed to fight another day, and even before we finished shaking out into battle formation, the dust cloud that signaled the location of their column began to rise in the air again as they reversed march to head back north. Resuming our own progress, as soon as we approached the hill from which they had observed us, we saw in the distance beyond that there was yet another formation a short distance behind the original column, traveling on a parallel track that was more to the east than the one that we had been observing. Seeing this other force, Caesar decided to wait and see what they would do, deciding that we had gone far enough that day and ordering us to make a marching camp on top of the hill. It was while we were in the process of making camp that a courier from the first column obviously made it to the second, because they also turned around to head back north, deciding to find better ground, which we expected. What we did not expect was that they would pick an island, or rather, a number of islands.
Over the next two days, we were never able to catch the Lucenses, although I am not altogether sure that Caesar wanted to, given the length of our marching column, strung-out as it was because of the terrain. Coming to the Minus (Guadiana) River, it was here that we ran into a challenge bigger than the one that we faced at the Douro. This river empties into the great ocean, and is guarded on both sides by high hills. On the opposite bank, there was a good sized fortified town, right at the mouth of the river and with a commanding view of the area. Compounding the problem, this was the best area for miles to build a bridge, but was out of the question because of the position of the town. There was no bridge in place; instead, the Lucenses were using a large number of flat-bottomed boats to ferry their army across, and we were greeted by a frustrating sight. Climbing the last hill of the opposite bank just in time to see the last boatloads cross, we could only stand helplessly and curse as of course they did not send the boats back. The Minus was too wide and deep to cross by fording; even a pontoon bridge at that location was out of the question because of the vulnerability to the Gallaeci army and the swift current as the river emptied into the ocean. Consequently, we would have to march upriver and Caesar wasted no time in giving that order. We were in the vanguard that day, so Caesar diverted the 9th to send them east up the river, while we now became the rearguard. A cavalry ala was left behind to keep watch on the Gallaeci in case they thought to go back across the river and follow behind us. To further forestall that, once we moved up the riverbank and crossed over another hill out of sight from the town, Caesar dropped the 8th, 9th, and 10th Cohort of our Legion off on the reverse slope, directing them to build a camp. By climbing the short distance up the hill to the summit, sentries could keep an eye on the Gallaeci to make sure that they did not come after us. If they did there would be a blocking force that could intercept them if they came onto our side of the river, or at the least warn us if they followed on the other side. We knew that we could not keep them from observing our actions, yet that did not mean we had to make it easy on them.