Vitudurum was a vicus in what is now Oberwinterthur during the Roman era (1st century BC to 3rd century AD).
It was fortified into a castrum at the end of the 3rd century, apparently in reaction to the incipient Alamannic invasion.

There was an Alamannic settlement on the site in the 7th century.

In a battle near Winterthur in 919, Burchard II of Swabia asserted his control over the Thurgau within the Duchy of Swabia against the claims of Rudolph II of Burgundy.

The counts of Winterthur, a cadet branch of the family of the counts of Bregenz, built Kyburg castle in the 10th century.
With the extinction of the counts of Winterthur in 1053, the castle passed to the counts of Dillingen.
Winterthur as a city (presumably on the site of a pre-existing village) was founded by Hartmann III of Dillingen in 1180, shortly before his death in the same year.
From 1180 to 1263, Winterthur was ruled by the cadet line of the House of Kyburg.

When the counts of Kyburg became extinct in the male line in 1263, Winterthur passed to the House of Habsburg, who established a comital line of Neu-Kyburg in 1264 and granted city rights to Winterthur in the same year.
From 1415 until 1442 Winterthur was reichsfrei (subject only to the Holy Roman Emperor).
However, in the Old Zürich War they lost this freedom and came back under the control of the Austrian Habsburgs.
Needing money, in 1467, the Habsburgs sold Winterthur to the city of Zürich.

While it was under the leadership of Zürich, Winterthur's economic freedom was restricted.
It lost many of its market rights and the right to trade in some goods.
This ended in 1798, when Napoleonic troops took the town.
On 27 May 1799, it was the site of the Battle of Winterthur between elements of the French Army of the Danube and elements of the Habsburg army, commanded by Friedrich, Baron von Hotze during the War of the Second Coalition, in the French Revolutionary Wars.
Because Winterthur lies near Zürich and at the junction of seven roads, the army that held the town held the access to most of Switzerland and points crossing the Rhine into southern Germany.
Although the forces involved were small, the ability of the Austrians to sustain an 11-hour assault against the French line, on the plateau north of Zürich, resulted in the consolidation of three Austrian forces.
This led to the French defeat a few days later.

In the 19th century, Winterthur became an industrial town when companies, like Sulzer, Rieter and SLM, built large industrial plants.
Winterthur suffered severely from its investments in and guarantee of loans to the National Railway of Switzerland (a private enterprise).
In 1878, Winterthur had to sell its shares in the line, and from 1881 to 1885 it was in great difficulties due to a loan of nine million francs guaranteed in 1874 by the town, together with three others in Aargau, to the enterprise.
As the three co-guarantor towns were unable to pay their shares, the whole burden fell on Winterthur, which struggled to meet its liabilities.
But it was assisted by large loans from the cantonal and federal governments.

The Great Depression, in the 1930s, hit Winterthur extremely hard.
Sixty percent of the total employees in town worked in the machine industry.
Jobs became extremely hard to find.
However, with the outbreak of World War II, industry grew again in the city.

In 2008, Winterthur reached 100,000 inhabitants.
Vitudurum was a vicus in what is now Oberwinterthur during the Roman era (1st century BC to 3rd century AD). It was fortified into a castrum at the end of the 3rd century, apparently in reaction to the incipient Alamannic invasion.
There was an Alamannic settlement on the site in the 7th century.
In a battle near Winterthur in 919, Burchard II of Swabia asserted his control over the Thurgau within the Duchy of Swabia against the claims of Rudolph II of Burgundy.
The counts of Winterthur, a cadet branch of the family of the counts of Bregenz, built Kyburg castle in the 10th century. With the extinction of the counts of Winterthur in 1053, the castle passed to the counts of Dillingen. Winterthur as a city (presumably on the site of a pre-existing village) was founded by Hartmann III of Dillingen in 1180, shortly before his death in the same year. From 1180 to 1263, Winterthur was ruled by the cadet line of the House of Kyburg.
When the counts of Kyburg became extinct in the male line in 1263, Winterthur passed to the House of Habsburg, who established a comital line of Neu-Kyburg in 1264 and granted city rights to Winterthur in the same year. From 1415 until 1442 Winterthur was reichsfrei (subject only to the Holy Roman Emperor). However, in the Old Zürich War they lost this freedom and came back under the control of the Austrian Habsburgs. Needing money, in 1467, the Habsburgs sold Winterthur to the city of Zürich.
While it was under the leadership of Zürich, Winterthur's economic freedom was restricted. It lost many of its market rights and the right to trade in some goods. This ended in 1798, when Napoleonic troops took the town. On 27 May 1799, it was the site of the Battle of Winterthur between elements of the French Army of the Danube and elements of the Habsburg army, commanded by Friedrich, Baron von Hotze during the War of the Second Coalition, in the French Revolutionary Wars. Because Winterthur lies near Zürich and at the junction of seven roads, the army that held the town held the access to most of Switzerland and points crossing the Rhine into southern Germany. Although the forces involved were small, the ability of the Austrians to sustain an 11-hour assault against the French line, on the plateau north of Zürich, resulted in the consolidation of three Austrian forces. This led to the French defeat a few days later.
In the 19th century, Winterthur became an industrial town when companies, like Sulzer, Rieter and SLM, built large industrial plants. Winterthur suffered severely from its investments in and guarantee of loans to the National Railway of Switzerland (a private enterprise). In 1878, Winterthur had to sell its shares in the line, and from 1881 to 1885 it was in great difficulties due to a loan of nine million francs guaranteed in 1874 by the town, together with three others in Aargau, to the enterprise. As the three co-guarantor towns were unable to pay their shares, the whole burden fell on Winterthur, which struggled to meet its liabilities. But it was assisted by large loans from the cantonal and federal governments.
The Great Depression, in the 1930s, hit Winterthur extremely hard. Sixty percent of the total employees in town worked in the machine industry. Jobs became extremely hard to find. However, with the outbreak of World War II, industry grew again in the city.
In 2008, Winterthur reached 100,000 inhabitants.
Winterthur