I found these pretty bulbs when we moved into this house.
This is what was printed on the box of ornaments:
During the dark ages, German natives in remote northern Bohemia originated an art form in glassblowing which not only holds a unique place in the 4000 year history of this ancient art, but has become a cherished part of Christmas tradition. The Germans had learned this skill (a heritage of Egypt) from wandering Venetian tradesmen. They used it to create glass ornaments for adornment of the Tannenbaum (fir tree) in their Yule celebration of the winter sun solstice. Early Christians adapted this custom of decorating the evergreen to their celebration of the birth of Christ, and thus the Christmas tree was born. Down through the centuries the German glass blowers of Bohemia became famous throughout the world for their blown glass Christmas tree ornaments.