Sultan Ghiyath al-Din Muhammad of the Ghurid dynasty chose the scarred plot of the burned mosque and additional land around it for his new congregational mosque. The Ghurids built the entire original structure in brick, a material that would prove more durable than anything that came before. When the Sultan died in 1203, he was buried in a mausoleum within the mosque he had founded. His son, Sultan Ghayath-ul-din Mahmood, continued the construction. But continuity was short-lived. In 1221, the Mongol armies of Genghis Khan swept through the province. Along with much of Herat, the mosque fell into ruin. For more than two decades the building sat damaged, until after 1245 when a king of the Kart dynasty, appointed by the Mongols as governor, undertook rebuilding.

After 1397, the Timurid rulers shifted Herat's center of gravity northward. They built a massive new congregational mosque in Gawhar Shad's Musalla Complex, and for a time the old Friday mosque lost its royal patronage. The Musalla's mosque was larger and more lavish -- a statement of Timurid ambition in stone and tile. But the old mosque endured. A marble minbar with nine steps replaced the original wooden pulpit. Mughals came and went. Uzbeks held the city and supported the mosque. Each dynasty added its layer, modified its spaces, left its mark. The fundamental Ghurid bones survived beneath the accumulating centuries of plaster and tile.

In 1885, officers of the British Indian Army made a decision that still echoes through Herat's skyline. Fearing that a Russian invasion force might use the Musalla Complex as a fortress, they dynamited the massive Mosque of Gawhar Shad and much of its surrounding complex. The architectural loss was staggering. But the Great Mosque, located in the heart of the old city rather than the northern suburbs, was spared. It became, by default, the primary congregational mosque of Herat once again -- not through any act of devotion but through the destruction of its rival.

Repair works in 1913 addressed the mosque's most urgent structural problems. Then, in 1942 and 1943, an extensive renovation fundamentally changed its appearance. Buildings that had grown up around the mosque over the centuries were demolished, making it a freestanding structure for the first time. A new east entrance rose with a high archway flanked by two minarets. The exterior walls received glazed tiles in the Timurid style, work guided by a ceramic tile studio established by UNESCO. That studio preserved the mosque's tile decorations and mosaics until 1979, when conflict once again disrupted the work. In 1992, the courtyard's stone plaster was replaced with alternating strips of white and black marble -- wide bands of white, narrow stripes of black -- but donations faltered and the project dragged on until 1998.

The Great Mosque of Herat is not a museum. It remains what it has been since 1200: a place where the faithful gather on Fridays for communal prayer and sermon. That continuity across more than eight hundred years, through Mongol destruction and earthquake and fire, through the rise and fall of dynasties speaking Turkic and Persian and Pashto, is the mosque's true achievement. The calligraphy on its walls is modern -- substituted by contemporary calligraphers during the 20th-century renovations. The tiles are reproductions in the Timurid style. The marble courtyard is barely a generation old. Yet the act performed within these walls each Friday is the same one that Sultan Ghiyath al-Din imagined when he laid the first bricks on the site of a Zoroastrian temple more than eight centuries ago.