Complex sentence: His date of birth was given in his obituary in "The Times" as 26 December 1792; but then a nephew wrote to say that Babbage was born one year earlier, in 1791.
Split into simpler sentences: His date of birth was given in his obituary in "The Times" as 26 December 1792. However after the obituary appeared, a nephew wrote to say that Charles Babbage was born one year earlier, in 1791.