Archeological evidence suggests that early settlements existed around 4000 B.C. in the Langenthal area.
A Hallstatt necropolis with twelve grave mounds has been found at Unterhard.
Remnants of two Roman villae have also been identified.

Langenthal is first mentioned in 861, as marcha in Langatun, referring to farming estates scattered along the Langete (a tributary of the Murg).
The Old High German name Langatun is presumably composed of a hydronym langa- and the Gaulish element dunum "fort" (which had become productive as a suffix in toponyms).

The re-interpretation of the name as including the element -tal "valley" dates to c. the 15th century, during which the name is on record as either  Langaten or  Langental (the same process can be observed in the case of Murgenthal, earlier Murgatun).

In the 12th century Langenthal (now known as Langaton) belonged to the territory of the lords of Langenstein.
In 1194 the Freiherr founded the Abbey of St. Urban and endowed the Abbey with lands in Langenthal.

Formerly part of Thunstetten parish, Langenthal was granted its own parish church in 1197.

After the extinction of the Langenstein family in 1212, the Abbey inherited additional lands in the area.
The establishment of the Abbey brought agricultural improvements, especially the introduction of an irrigation system to the area.
However, the Abbey often came into conflict with the Kyburg Ministerialis (unfree knights in the service of a feudal overlord) family of Luternau.
The Luternau family fought the growing power of the Abbey, until 1273-76 when they were obligated to sell their interest in Langenthal to the Abbey.
Just a few years later, in 1279, the Abbey, in turn, was forced to give the low court and a fortified house in Langenthal to the Freiherr of Grünenberg to hold as a fief.
By the end of the 14th century, the Abbey had regained power and was able to bring the village fully under their control.

Starting in 1313 the Kyburgs held the high court right for the village.
When that family died out in 1406, Bern inherited the right to hold the high court.
Over the next few years Bern's power expanded in Langenthal.
In 1415, Langenthal became incorporated into the territory of the Republic of Bern, but it remained under the landlordship and the low court of the monastery.
Over the following centuries, the Bernese court slowly eliminated many of the Abbey's powers.
The Protestant Reformation of 1528 weakened the power of the Abbey slightly, but it continued to collect tithes and appoint the village priest until Bern bought those rights in 1808.

During the 16th century a number of craftsmen and small businesses moved into the growing town.
In 1571 Bern granted the right for the town to hold two yearly markets.
However, the supply of goods for sale quickly exceeded the capacity of the two yearly markets.
In 1613 they built a Kaufhaus or market building and started holding weekly markets.
The Kaufhaus was rebuilt in 1808 and from 1894 until 1992 served as the town hall.
By 1616 Langenthal had a series of laws and regulations governing the booming markets and trade in the town.
In 1640 Langenthal and Langnau became centers of linen canvas production and export to France, Italy, Spain and Portugal.
In 1704 Langenthal became the seat of the Oberaargau canvas dealer's guild, which brought together weavers, shopkeepers and traders to protect their interests.
The decline of eastern Switzerland's linen industry in the 18th century gave Langenthal a further boost, which encouraged to Bern to tighten supervision.
Beginning in 1758 the Bernese government started inspecting cloth for quality and controlling who was allowed to sell.

The success of the linen trade helped the town to grow.
Even though the Aargau cantonal road bypassed the Langenthal, by 1756 it had grown to a total of 189 households, three taverns, various administrative buildings and a warehouse (dated 1748).

The market street was paved in 1730 and the Langete was partially covered with stone bridges and new houses.
In 1785 a brewery opened in town.
A small elite of merchant
Archeological evidence suggests that early settlements existed around 4000 B.C. in the Langenthal area. A Hallstatt necropolis with twelve grave mounds has been found at Unterhard. Remnants of two Roman villae have also been identified.
Langenthal is first mentioned in 861, as marcha in Langatun, referring to farming estates scattered along the Langete (a tributary of the Murg). The Old High German name Langatun is presumably composed of a hydronym langa- and the Gaulish element dunum "fort" (which had become productive as a suffix in toponyms).
The re-interpretation of the name as including the element -tal "valley" dates to c. the 15th century, during which the name is on record as either  Langaten or  Langental (the same process can be observed in the case of Murgenthal, earlier Murgatun).
In the 12th century Langenthal (now known as Langaton) belonged to the territory of the lords of Langenstein. In 1194 the Freiherr founded the Abbey of St. Urban and endowed the Abbey with lands in Langenthal. 
Formerly part of Thunstetten parish, Langenthal was granted its own parish church in 1197.
After the extinction of the Langenstein family in 1212, the Abbey inherited additional lands in the area. The establishment of the Abbey brought agricultural improvements, especially the introduction of an irrigation system to the area. However, the Abbey often came into conflict with the Kyburg Ministerialis (unfree knights in the service of a feudal overlord) family of Luternau. The Luternau family fought the growing power of the Abbey, until 1273-76 when they were obligated to sell their interest in Langenthal to the Abbey. Just a few years later, in 1279, the Abbey, in turn, was forced to give the low court and a fortified house in Langenthal to the Freiherr of Grünenberg to hold as a fief. By the end of the 14th century, the Abbey had regained power and was able to bring the village fully under their control.
Starting in 1313 the Kyburgs held the high court right for the village. When that family died out in 1406, Bern inherited the right to hold the high court. Over the next few years Bern's power expanded in Langenthal. In 1415, Langenthal became incorporated into the territory of the Republic of Bern, but it remained under the landlordship and the low court of the monastery. Over the following centuries, the Bernese court slowly eliminated many of the Abbey's powers. The Protestant Reformation of 1528 weakened the power of the Abbey slightly, but it continued to collect tithes and appoint the village priest until Bern bought those rights in 1808.
During the 16th century a number of craftsmen and small businesses moved into the growing town. In 1571 Bern granted the right for the town to hold two yearly markets. However, the supply of goods for sale quickly exceeded the capacity of the two yearly markets. In 1613 they built a Kaufhaus or market building and started holding weekly markets. The Kaufhaus was rebuilt in 1808 and from 1894 until 1992 served as the town hall. By 1616 Langenthal had a series of laws and regulations governing the booming markets and trade in the town. In 1640 Langenthal and Langnau became centers of linen canvas production and export to France, Italy, Spain and Portugal. In 1704 Langenthal became the seat of the Oberaargau canvas dealer's guild, which brought together weavers, shopkeepers and traders to protect their interests. The decline of eastern Switzerland's linen industry in the 18th century gave Langenthal a further boost, which encouraged to Bern to tighten supervision. Beginning in 1758 the Bernese government started inspecting cloth for quality and controlling who was allowed to sell.
The success of the linen trade helped the town to grow. Even though the Aargau cantonal road bypassed the Langenthal, by 1756 it had grown to a total of 189 households, three taverns, various administrative buildings and a warehouse (dated 1748). 
The market street was paved in 1730 and the Langete was partially covered with stone bridges and new houses. In 1785 a brewery opened in town. A small elite of merchant
Langenthal