In the 5th century BC, a certain Roman engineer was appointed to direct the construction of a bridge over the river Leza. The bridge was important for the area. People and goods would be able to use it to cross the river, saving time and avoiding travelling long distances looking for a safe place to ford the river.

The engineer received this appointment with great enthusiasm, and went on to plan an estimate for everything that would be needed for the construction. He calculated how many builders, cranes, pulleys, scaffolds and centrings would be necessary. He could clearly see that with 50 builders the bridge could be finished in 4.7 years.

With the 600,000 sestertii that he had received to execute this assignment, he quickly bought all the necessary materials according to his calculations, and had them delivered to the construction site. He recruited the 50 builders he had estimated he would need and sent them to the river bank to start work at soon as possible. There was no time to lose. The sooner it was begun, the sooner it would be finished.

Soon, however, the workers told him that they didn’t need so many pulleys and cranes, but that there weren’t enough pickaxes and saws for the job. “I can’t do anything about that,” said the engineer, “most of the money has already been spent and there isn’t much left to buy new materials. You’ll have to adapt to what we’ve got.”

The construction went on, and soon afterwards it became clear that things weren’t going as planned. The foreman told the engineer that the stone quarry where the stone was being cut was too far away, and that the road was full of bumps and potholes from last year’s flooding. It just took too long to bring the stone in carts to the bridge. “You’ll have to make an extra effort,” said the engineer, “there’s no time now to fix the road.”

The foreman also informed the engineer that it would be necessary to build arches in the bridge, to reduce the amount of materials used, and, most of all, to improve its resistance. “There’s no time for frills,” said the engineer. “We’re late. We’ll add a little extra mortar in the pillars, and that’ll be it.”

The news about the construction of the bridge came to the Prefect’s ears. He despaired when he heard about how slowly the work was progressing, so he sent for the engineer. The Prefect needed to justify his actions in Rome, and demanded that the bridge be ready for Saturnalia. The engineer explained that, in order to achieve that, he would need at least another 50 workers. As he was also pressured from above, the Prefect agreed and committed to send the new workers a month later.

Back at the bridge, the engineer gathered all the builders and asked them for an additional effort to comply with that new deadline. The workers could not understand how were they to work twice as fast if they didn’t have enough stone, and in any case they always had to wait for the mortar to set.

Not even with the new workers could the bridge be built on time. There weren’t enough tools for everyone, the stone was still slow reaching the worksite, and collapses were common because of the hurried construction process.

In ancient Rome, a bridge’s builders had to stand underneath it while an entire legion crossed it. It’s a good incentive to build firm, solid bridges, don’t you think?