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The Legendary Trajan’s Bridge — The Astonishing Architectural Achievement of Antiquity
By Peter Preskar, Medium, 11/5/22
May 16, 2022 - 11:30:39 AM

Trajan’s Bridge over the Danube River was the longest arch bridge for over 1,000 years

In order to supply his legions fighting in Dacia, Roman Emperor Trajan ordered the construction of a 1,135 meters (3,724 feet) bridge across the Danube River. Apollodorus of Damascus, one of the best Roman architects, designed a fantastic bridge with stone pillars and a wooden superstructure.

The bridge was fifteen meters (forty-nine feet) wide. It was nineteen meters (sixty-two feet) above water.

The Trajan’s Bridge was high enough to allow the ships to pass beneath.

The bridge enabled the Romans to move supplies and troops quickly over the Danube River and thus greatly contributed to the Roman conquest of Dacia in 106.

The Romans needed just three years to build a one-kilometer long bridge

The Romans needed only three years, from 103 to 105 AD, to complete the bridge. That was an astonishing feat since the bridge was 1,135 meters (3,724 feet) long.

Apollodorus diverted the river to dry out the river bed and made it possible to construct the pillars made of bricks and mortar.

The Romans used oak wood for the arches. The wooden superstructure was assembled on land and then installed on pillars.

Wooden arches, each spanning thirty-eight meters (125 feet), rested on twenty massive masonry pillars.

Pillars were forty-four meters (145 feet) tall, seventeen meters (fifty-eight feet) wide, and fifty meters (165 feet) apart.

The greatest achievement of the Roman civil engineering

For more than 1,000 years, the Trajan’s Bridge was the longest arch bridge in the world by total and by span length.

On both sides of the bridge was a fortress that controlled the entrance to the bridge.

Emperor Trajan (reigned 98-117), master of propaganda, made sure each side of the bridge was decorated with a huge statue depicting him.

The Trajan’s Bridge was destroyed out of jealousy

The main purpose of the Trajan’s Bridge was to support the logistics of large-scale military operations in Dacia.

With the conquest of Dacia being completed in 106 AD, the bridge began posing a weak point in the Roman defense line.

The barbarians who would overpower the bridge’s garrison could easily cross the Danube River and invade the Roman Empire.

Despite the defense risk, the real reason for the wooden superstructure of the bridge being destroyed was jealousy.

Trajan’s successor Hadrian (reigned 117-138) served as a general during the Dacian Wars and was personally very interested in architecture.

When Trajan’s main architect Apollodorus of Damascus showed Trajan the plans for the future bridge, Hadrian added a few comments.

Apollodorus rebuffed and ridiculed Hadrian for his knowledge of architecture.

Hadrian never forgot the insult and when he ascended the throne following Trajan’s death, he banished and later executed Apollodorus.

Jealous of obvious Apollodorus’ talent for architecture, Hadrian ordered the destruction of the wooden superstructure. He wanted to destroy not only the architect but also his greatest achievement.

Conclusion

In 328, Emperor Constantine (reigned 306-337) led a military expedition against the Goths. He rebuilt the bridge to support a quick crossing of the Danube River.

However, the subsequent attacks by the Goths and the Huns forced the Romans to dismantle the bridge once and for all.

The once-formidable bridge slowly faded out of human memory.

The remnants of the bridge’s pillars reappeared in 1858 when the level of the Danube was extremely low because of severe drought.

By 1982, only twelve out of twenty original pillars remained.