The Roman Empire is often romanticized, especially by the media and history buffs, as one of the most advanced ancient civilizations who enjoyed 1,480 years of ultimate power. But their reign was one that was marked by a series of highs and lows brought on by the numerous enemies they made along the way. Though for all their military prowess, the Romans have actually lost countless battles, namely at the hands of these five armies in this list below.

1. The Ottoman Empire

Without a doubt, the Ottoman Empire was one of the biggest thorns in the Eastern Roman Empire’s side, or the Byzantine Empire. It was so bad that they even had to seek help from other western powers in order to make up for the embarrassing one-sided beatings. But in April of 1453, Sultan Mehed II decided to eliminate the Romans once and for all by having his forces besiege the capital, Constantinople. He continued to do so over the course of 55 days, finally achieving what no one else could: bring down Constantinople’s famous impenetrable walls.

2. The Cherusci

One of the Roman Empire’s earliest humiliating defeats was during the Battle of the Teutoburg Forest, also known as the Varian Disaster. It was appropriately called so due to the fact that three legions and the auxiliaries were entirely wiped out. Long story short, the Roman Empire had their sights set on the Germanic Cherusci tribe as part of their great expansion. Publius Quincilius Varus, the Roman general leading the charge, led his guard down since the tribe’s prince Arminius was on good terms with Rome. Instead the opposite happened: Arminius plotted a revolt, then ambushed the Romans while they were passing through the Teutoburg Forest.

3. The Sasanian Empire

In the early years, the Roman and Sasanian Empires frequently fought against each other, though the Romans always came out on top. At some point, they decided to put their differences aside by agreeing to a treaty. But that came to an end a mere ten years later when King Shapur launched a surprise attack in 260 AD, pillaging their cities in the process. Still not satisfied, he started yet another military campaign which led to Emperor Valerian’s eventual capture and death in captivity.

4. The Senones

To be fair, this defeat took place at a time when the Roman Empire was already down on their luck, having been the victim of several previous attacks. The Senones were a tribe of Gauls who originally settled in the basin of the River Seine, led by their chieftain, Bennus. Their squabble with the Romans took place around 390 BC at the Battle of Allia, which was a clear cut victory for the Senones. Shortly after, the victors marched straight into the heart of Rome, plundered the capital, burned down buildings and stole its valuables.

5. Parthia

And then there was Parthia, an Iranian civilization and one of Rome’s biggest threats. The two frequently clashed as both sought to expand their empires over Mesopotamia where Parthia ruled. However, the most prominent war took place in 53 BC during the Battle of Carrhae when the Romans suddenly attacked the Parthians only for the latter to gain the upper hand and decimate their army. Of the 35,000 soldiers, 20,000 were killed, 10,000 captured and a measly 5,000 managed to escape. It is said that their 160-year-long conflict finally came to an end when the Sassanid Empire conquered Parthia, only for them to start beefing with the Romans as well.