Question: When did the financial crisis start in 2008?

Disambiguated questions and answers:
context: No context provided
question: On what date did the financial crisis of 2008 actually start happening?
short_answers: April 2007
context: No context provided
question: Upon what 2007 event did the financial crisis of 2008 start happening?
short_answers: depreciation in the subprime mortgage market
context: It began in 2007 with a crisis in the subprime mortgage market in the United States, and developed into a full-blown international banking crisis with the collapse of the investment bank Lehman Brothers on September 15, 2008. Excessive risk-taking by banks such as Lehman Brothers helped to magnify the financial impact globally. Massive bail-outs of financial institutions and other palliative monetary and fiscal policies were employed to prevent a possible collapse of the world financial system. The crisis was nonetheless followed by a global economic downturn, the Great Recession. The Asian markets (China, Hong Kong, Japan, India, etc.) were immediately impacted and volatilized after the U.S. sub-prime crisis. The European debt crisis, a crisis in the banking system of the European countries using the euro, followed later.
question: On what date did the financial crisis in 2008 start developing into a full-blown international banking crisis?
short_answers: September 15, 2008
wikipage: Financial crisis of 2007–08
context: It began in 2007 with a crisis in the subprime mortgage market in the United States, and developed into a full-blown international banking crisis with the collapse of the investment bank Lehman Brothers on September 15, 2008. Excessive risk-taking by banks such as Lehman Brothers helped to magnify the financial impact globally. Massive bail-outs of financial institutions and other palliative monetary and fiscal policies were employed to prevent a possible collapse of the world financial system. The crisis was nonetheless followed by a global economic downturn, the Great Recession. The Asian markets (China, Hong Kong, Japan, India, etc.) were immediately impacted and volatilized after the U.S. sub-prime crisis. The European debt crisis, a crisis in the banking system of the European countries using the euro, followed later.
question: Upon what event did the financial crisis in 2008 start developing into a full-blown international banking crisis?
short_answers: collapse of the investment bank Lehman Brothers
wikipage: Financial crisis of 2007–08

Long-form answers:
long_answer: In April 2007 the depreciation in the subprime mortgage market initiated the financial crisis. This crisis later turned into a full-blown international banking crisis by September 15, 2008, because of the collapse of the investment bank Lehman Brothers. 
long_answer: The 2008 financial crisis began and started developing into an international banking crisis on different dates and after different events. It actually started happening in April 2007 when the 2007 depreciation in the subprime mortgage market occurred. It started developing into a full-blown international banking crisis on September 15, 2008, upon the collapse of the investment bank Lehman Brothers.