"A second world war began when the armies of Great Germany marched..."
First time I've noted the phrase, "a second world war" -- probably used before, but I missed it.
Have yet to see phrases like, "The Second World War" or "World War Two" or "WWII".
Hanson Baldwin used the term “second World War” as far back as September 1939, but note that the word “second” is not capitalized making it a comparative to the World War earlier this century, but not an official title. Though I’ve seen “second World War” a few times now, it still has not been presented in a way like you mention “Second World War” or “World War II”. I’m interested to see when it officially starts being called World War II.