The House of Habsburg, which held the throne of the Holy Roman Empire from 1438 – 1740 and ruled Austria till 1918, spread the Loreto cult all over its empire. This was part of the efforts to stem the tide of Protestantism with a Counter-reformation. Loreto, with its Holy House of Mary, where the annunciation of Christ’s birth is said to have taken place, became a central piece of the Counter-reformation. The Marian litany of Loreto and more or less exact copies of the Holy House with its Black Madonna spread all over Europe. The German Wikipedia article on “ Loretokapelle” lists 16 Loreto chapels in Austria, 40 in Germany, etc. There used to be many more in Austria, but as times changed, quite a few of the Black Madonna chapels were transformed into different kinds of chapels.