In cathedrals built in the High Gothic period, the structural system made it possible a significant enlightening of the structure and opening of the perimeter walls by large window openings. On their glazing, composed of small panes of multi-coloured glass, artists created amazing pictures with figures of saints or scenes from the Bible. With such window pictures, the cathedral of St. Vitus at Prague Castle had been equipped since it was built from 1344. However, due to fateful misfortune, the medieval stained glass windows in it - except for two small fragments - have not been preserved. The colourful glazing of windows that visitors to the cathedral can see today were created over a period of approximately one hundred years (1865–1969). All but the windows in the chapel of St. Wenceslas come from the era of completion and repairs carried out by the Union for the completion of the cathedral of St. Vitus at Prague Castle (further, simply Jednota). Their implementation was only made possible by generous financial donations from institutions (e.g. insurance companies or savings banks) and individuals; there were even donors who did not want to be named. Artistic designs were ordered from a number of designers among whom were well-known artists (e.g. Max Švabinský, Karel Svolinský, Cyril Bouda, Alfons Mucha). The first two modern cathedral builders, Josef Kranner and Josef Mocker also participated in the designs. A number of sketches and detailed worked on paperboards, according to which the stained glass windows were made, have survived. The oldest surviving windows were made by Jan Zachariaš Quast, after which production was entrusted to the Tyrolean glassworks for glass paining and cathedral glass in Innsbruck, for more than thirty years. Stained glass windows from the period of the First Republic were realized by the domestic companies of Jan Jaroš, Josef Vlasák, Josef Jiřička and Jan Veselý.