Alexander arrived at Hecatompylos during his relentless eastward campaign, using it as a staging point before pushing into Central Asia. After his death, the city passed to the Seleucid Empire, his successors' attempt to hold together his conquests. Around 237 BCE, the Parni tribe -- nomadic warriors from the Central Asian steppes -- seized the city and made it one of the foundational capitals of what became the Parthian Empire, which would eventually stretch from the Euphrates to the Indus. Classical writers documented the city's importance. Strabo, Pliny the Elder, and Ptolemy all mentioned Hecatompylos as a royal city of the Parthians, though the empire used several cities as capitals at different periods, moving its court between Hecatompylos, Ctesiphon, and other centers of power as politics and warfare demanded.

The Persian name Qumis carries the same meaning as the Greek -- 'a hundred gates' -- a rare case where conqueror and conquered agreed on what to call a place. The city sat along the Great Khorasan Road, the ancient highway connecting Mesopotamia to Central Asia, making it a natural crossroads of trade, military movement, and cultural exchange. Its location in the Qumis region of western Khorasan placed it at a geographic hinge point where the Alborz Mountains to the north give way to the vast deserts of the Iranian plateau to the south. Control of this corridor meant control of east-west traffic across the entire northern tier of the Persian world. For over a millennium, whoever held Qumis held a key to the region.

In 856 CE, an earthquake struck the city of Damghan and its surroundings with catastrophic force. The 856 Damghan earthquake is estimated to have killed approximately 200,000 people, making it one of the deadliest earthquakes in recorded history. Qumis, already declining from its Parthian-era prominence, was destroyed. The city was likely abandoned afterward, its population scattered to nearby settlements. What remains today is a low archaeological site between the modern cities of Semnan and Damghan in Semnan province -- mounds and scattered surface finds that hint at the layers of civilization beneath. The site has never been comprehensively excavated, leaving its full story buried in the ground where it has rested for over a thousand years.

In 2011, plans were announced for an 'International Project of Tourism and Recreational City' near Damghan using the ancient name Hecatompylos. The proposed development would cover 250 hectares, placed about 30 kilometers northeast of the actual historic site. The project reflects the recurring tension between modern development and archaeological preservation in Iran. The ruins of Shahr-e Qumis themselves remain largely unstudied. Scholars have debated the precise identification of the site with the ancient Hecatompylos, though most now accept the connection. What lies beneath the surface -- Parthian palaces, Seleucid administrative buildings, earlier Persian structures -- remains a matter of speculation and occasional surface finds. For now, the City of a Hundred Gates keeps its secrets in the dust of the Iranian plateau, waiting for the archaeologists who may one day open those gates again.