Muslin is a loosely constructed, plain weave fabric, woven in a variety of forms and weights. High quality muslins are created from fine, smooth, evenly spun thread, resulting in a soft, breathable fabric.
Muslin was once a valuable commodity and has been traded around the world throughout human history, dating back to ancient India. Known as a luxury fabric, muslin from ancient India was handwoven using extremely fine, hand-spun yarns. The material was first made and named in the city of Mosul, which is now in Iraq. During the 17th and 18th centuries, Mughal Dhaka was capital of the worldwide muslin production. Highly popular in 18th-century France, the desire for muslin eventually spread across much of the Western world. It was praised in the international market as "woven wind" and "wonder gossamer" and was as expensive as silk.
During British colonial rule in India and Bangladesh, muslin weavers were not treated well and were not permitted to weave muslin, while Europe took over muslin production, creating machine-woven substitutes. Gandhi, the leader of the Indian independence movement, started spinning yarn himself to make khadi, a type of muslin, to promote self-reliance and to peacefully resist British rule. 
Today, muslin is woven all over the globe and is used in a variety of ways. There are four main grades of muslin:
Gray Heron’s blankets are made of lightweight, buttery soft, breathable gauze, woven in India.
Interested in learning more?
The ancient fabric that no one knows how to make: https://www.bbc.com/future/article/20210316-the-legendary-fabric-that-no-one-knows-how-to-make
The history of muslin: https://savageuniversal.com/blog/history-of-muslin/
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https://www.britannica.com/topic/muslin
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