Donna,
 
Yes, the Roman Empire as it existed in the Apostle John's day did indeed encompass a great deal of territory which fell to the Mohammedan onslaught in the 7th century. I think the issue here, however, is one of continuity.
 
As John wrote the Revelation, the Eastern Roman Empire as an entity was still in the future. When it was created by Diocletian in the 4th Century, it remained a predominantly Greek territory. It stopped being remotely Roman around 788 A. D. Therefore there is no continuity with the modern day, in which we expect to see the eventual rise of the empire represented by the feet and toes of Daniel's image.
 
By continuity, I mean that the feet are physically connected to the legs, in the same way the golden head was connected to the silver breast. This connection seems to represent time. When the gold stopped, for example, so did the Babylonian Empire. When the Silver stopped, the Brass of Alexander's reign began.
 
There is continuity, however, if we look at the Western Empire--the truly Roman Empire. It still exists in the form of the Roman Catholic Church (quite literally here), and in a great deal of underlying European and Western culture. The languages of France, Spain, Italy, and Portugal descend from Latin--the language of Rome. France, Germany, Spain and Italy all have undeniable Roman heritage. The rise of Islam destroyed any type of temporal or cultural continuity which might have been found in the Eastern Empire.
 
Now, from a purely geopolitical standpoint, the idea that the Moslem world could rise and overtake the present Western democracies is still highly unlikely. And in the event that they did, current sentiment in the Islamic world is extremely anti-Israel. If the Western world was suddenly absent, Israel could still very easily take care of itself if pushed to the wall by the Islamic nations which surround it. Israel is believed to currently have around 200 nuclear devices, as well as submarines from which to launch some of them if a doomsday scenario ever becomes necessary. Indeed, Israel undoubtedly has the ability to punish with nuclear weapons any nation on the earth if need be. "Never again," is the hue and cry of the Holocaust survivor.
 
Islamic radicals of the world, with their penchant for suicide attacks, are proving themselves to be people who are impossible to live with. It's only a matter of time before a fanatical Moslem group goes too far with the wrong party. When a culture loves death more than life, they will eventually get what they love the most.
 
Your brother in Christ,
Matt in Hayward, CA