The document summarizes the biblical prophecy of the 6th trumpet in Revelation and provides historical context relating to the fall of the Ottoman Empire. It describes how the 6th trumpet was fulfilled through the loosening of "four angels" which represented the four principal sultanates of the Ottoman Empire along the Euphrates River. These sultanates gained independence starting in 1449 and led to the conquest of Constantinople in 1453, ending the Byzantine Empire. The period of the Ottoman supremacy over Greece and the Eastern Roman Empire lasted 391 years and 15 days, until August 11, 1840 when the Ottoman Empire voluntarily surrendered independence.