Those are some old pants! Archaeologists have discovered what are likely to be the oldest pair of pants ever discovered - riding trousers estimated to be 3,000 years old.

Two pairs of pants in all were discovered in the Yanhjai tombs, ancient burial grounds in the Tarim Basin of western China. According to a study published in the journal Quaternary International, these all-wool garments are likely the oldest trousers ever found, and provide significant insight into the evolution of clothing from times between the 13th and 10th century BC.

So what could be so important about a pair of really old pants? Xiao Li of the School of Chinese Classics at Renmin University of China worked with experts from Berlin to uncover the pants, pieced them together, and analyze their structure.

The resulting analysis showed that the pants "were shaped on the loom, and they were shaped in the correct size to fit a specific person," indicating that people of the time were familiar enough with tailoring processes to craft custom fits, even when pants were not common dress code for the time.

Additionally, "the yarns... and threads for final sewing match in color and quality, which implies that the weaver and the tailor was the same person or that both cooperated in a highly coordinated way."

It is common belief that the evolution of the trouser originated from a simple design to help maintain comfort when riding horses. The study indicates that the design of these two ancient pairs of pants support that theory, as the craft of the pants is similar to subsequent riding trousers that had specifically-placed stitching to help a wearer avoid skin irritation and discomfort while riding.

The pants were also reportedly discovered alongside a wooden horse bit, a whip, and a bow, further supporting this theory.

The study was published in Quaternary International on May 22.