Apple’s chosen internet browser is Safari; they use it on their Mac computers and on the Apple iPhone with Mobile Safari, however apparently Mobile Safari wasn’t Apple first choice for the Apple iPhone internet browser.
Originally Apple wanted the Opera browser on their iPhone and was in talks with Opera for over 6 months in an attempt to have Opera browser as default to the Apple iPhone.
Something went wrong and it didn’t work out as intended, the deal fell through and thus Apple resorted to having their own Safari Mobile as default to the iPhone.
One does wonder why Apple didn’t want their own Safari Mobile as default for the iPhone.
Source — iphoneworld