In which decade were blue jeans, later made famous by Levi Strauss and others, first invented and introduced as durable work trousers?

Introduction / Context:
Blue jeans are now a global fashion item, but they began as practical work trousers made from durable denim for miners and labourers. Understanding when they were first invented and introduced helps place this clothing innovation in the wider history of industrial clothing. This question focuses on the decade in which blue jeans first appeared.

Given Data / Assumptions:

• The subject is blue jeans, not just denim fabric.
• The invention refers to riveted denim work trousers.
• The options are decades across the nineteenth and early twentieth centuries.
• We assume familiarity with the idea that jeans originated in the United States during the gold rush and railway expansion era.

Concept / Approach:
The first patented blue jeans with riveted pockets are connected with Levi Strauss and a tailor partner in the early eighteen seventies. While denim fabric existed earlier, the specific garment that became known as blue jeans was developed in this period. Therefore, we look for the decade that includes the early eighteen seventies, which is the 1870s.

Step-by-Step Solution:
Step 1: Recall that the key jeans patent and commercial introduction took place around the early eighteen seventies. Step 2: Recognise that the eighteen seventies fall within the 1870s decade. Step 3: Note that earlier decades such as the 1850s or 1860s were important for denim as a material, but not for the classic riveted jeans design. Step 4: Therefore, the correct answer is that blue jeans were invented in the 1870s.

Verification / Alternative check:
A simple check is to pair jeans with the post gold rush expansion era in the American West, when sturdy trousers for miners and railroad workers became essential. This period is slightly after the initial gold rush years of the eighteen fifties and belongs firmly in the eighteen seventies. Many general knowledge summaries list the early eighteen seventies as the invention period for blue jeans, reinforcing the 1870s choice.

Why Other Options Are Wrong:

• 1900s: By this decade, jeans already existed and were being worn, so this is too late for the invention.
• 1850s: Denim and work clothes were present, but the specific riveted jeans design had not yet been patented and popularised.
• 1860s: This decade is still slightly early for the classic jeans patent associated with Levi Strauss.
• 1880s: Jeans were already in use by this time, so it cannot be the invention decade.

Common Pitfalls:
Learners sometimes confuse the invention of denim fabric with the invention of jeans as a garment. Others assume that jeans are a modern twentieth century fashion item and pick 1900s by mistake. To avoid such errors, remember that jeans began as industrial workwear in the late nineteenth century, specifically in the 1870s, and only later became a global style statement.

Final Answer:
Blue jeans were first invented and introduced as durable work trousers in the 1870s.