Today, in Russian cities and even in some villages, you can see plastic windows. In the past, this was not the case, and glass was considered a very expensive material, so people used makeshift means.

In Ancient Rus, our ancestors often stretched a "payus," a film bag where fish roe is found, over small windows. They stretched it and wrapped it in several layers, creating a cloudy but transparent analogue of glass that let in light. Sometimes peasants used the light skin of large carp, cleaned it of scales, dried it in the sun, and hung it on windows. Another popular method was using a bull's bladder. In winter, they sometimes inserted ice.

However, the most popular material in Rus was mica, a layered natural mineral. Mining and polishing mica were considered important crafts. Russian mica was one of the best in Europe and was called "muscovite." However, it was expensive, and only princes, noble boyars, and sometimes wealthy peasants could afford it. Over time, the extraction and processing of mica expanded, and it became widely used throughout Rus.

Interestingly, "muscovite" not only let in light but also protected the home from wind, insects, and small animals. Starting in the 17th century, glass began to be inserted into windows in Russia, but initially only in royal palaces, as it was very expensive. However, progress did not stand still, and Russian craftsmen quickly mastered mass production of glass, which gradually replaced mica.