The Byzantine Empire began to fall due to ?

The Byzantine Empire fell in 1453. The immediate cause of its fall was pressure by the Ottoman Turks  during the reign of Constantine XI

Explanation:

increasing defense spending.

explanation:

mount st. helens in washington erupts, causing a massive avalanche and killing 57 people on this day in 1980. ash from the volcanic eruption fell as far away as minnesota. seismic activity at mount st. helens, which is 96 miles south of seattle, began on march 16.