Last year, British historian Simon Elliott published a book titled Alexander the Great versus Julius Caesar: Who was the Greatest Commander in the Ancient World?
I haven't read the book, but in my opinion the question is very easily settled. Julius Caesar was vastly superior. He won more...
Here is the summary of the worst military debacles suffered by the Romans during over 1000 years of history from the beginning of the Republic to the end of the Western Roman Empire.
In chronological order:
Battle of Heraclea (280 BCE)
Type of battle : pitched battle