What Battle was of Greater Importance?

[Geoffrey S]

Tours was of exaggerated importance, exaggerated by later writers wishing to emphasize the Muslim threat to Christianity, with exaggerated figures. As for the siege of Vienna, for the moment it may have been important, but the rot had been settling in the Ottoman Empire for some time before and failure to take Vienna can be seen as a result of those problems.

In both cases, the events were products of longer-running processes which were of infinitely larger importance than the historically memorable moments they produced. Both empires had reached their limits not due to Christian triumph against the odds, but the limits hit upon by overstretched empires. They couldn't expand further, let alone hold such gains.