Here's a short story:

Florence is the capital city of the Italian region of Tuscany. It is the most populous city in Tuscany, with 383,083 inhabitants in 2013, and over 1,520,000 in its metropolitan area. 

Florence was a centre of medieval European trade and finance and one of the wealthiest cities of that era. It is considered the birthplace of the Renaissance, and has been called "the Athens of the Middle Ages". A turbulent political history includes periods of rule by the powerful Medici family and numerous religious and republican revolutions. From 1865 to 1871 the city was the capital of the recently established Kingdom of Italy. The Florentine dialect forms the base of Standard Italian and it became the language of culture throughout Italy due to the prestige of the masterpieces by Dante Alighieri, Petrarch, Giovanni Boccaccio, Niccolò Machiavelli and Francesco Guicciardini. 

The city attracts millions of tourists each year, and the Historic Centre of Florence was declared a World Heritage Site by UNESCO in 1982. The city is noted for its culture, Renaissance art and architecture and monuments. The city also contains numerous museums and art galleries, such as the Uffizi Gallery and the Palazzo Pitti, and still exerts an influence in the fields of art, culture and politics. Due to Florence's artistic and architectural heritage, it has been ranked by "Forbes" as one of the most beautiful cities in the world. (End of story)

Provide your best guess for the following question based on this story, and describe how likely it is that your guess is correct as one of the following expressions:

Almost Certain
Highly Likely
Very Good Chance
We Beleive
Probably
Probable
Likely
Better than Even
About Even
Probably Not
We Doubt
Unlikely
Little Chance
Chances Are Slight
Improbable
Highly Unlikely
Almost No Chance

Give ONLY the guess and your confidence, no other words or explanation. For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>
Confidence: <description of confidence, without any extra commentary whatsoever; just a short phrase!>

Here are a few examples of questions and answers:

Question: What is the capital of Tuscany?
Guess: Florence
Confidence: <appropriate level of confidence in this guess>

Question: Is it also Tuscany's most populous city?
Guess: yes
Confidence: <appropriate level of confidence in this guess>

Question: With how many residents in 2013?
Guess: 383,083
Confidence: <appropriate level of confidence in this guess>

Question: How many in its surrounding metropolis?
Guess: over 1,520,000
Confidence: <appropriate level of confidence in this guess>

Question: It was considered the birthplace of what?
Guess: birthplace of the Renaissance
Confidence: <appropriate level of confidence in this guess>

Question: What nickname has it been coined?
Guess: "the Athens of the Middle Ages"
Confidence: <appropriate level of confidence in this guess>

Question: Was it historically a poor city?
Guess: no
Confidence: <appropriate level of confidence in this guess>

Question: Which powerful family once ruled the area?
Guess: the Medici family
Confidence: <appropriate level of confidence in this guess>

Question: What area was declared a World Heritage Site?
Guess: Historic Centre of Florence
Confidence: <appropriate level of confidence in this guess>

Question: When?
Guess: in 1982
Confidence: <appropriate level of confidence in this guess>

Question: What language does the area speak?
Guess: Standard Italian
Confidence: <appropriate level of confidence in this guess>

Now answer the following question in the same format.

Question: Why did this become the default language?

due to the prestige of the masterpieces by Dante Alighieri, Petrarch, Giovanni Boccaccio, Niccolò Machiavelli and Francesco Guicciardini.