Simple english ?
well, know your majesty before all things called lazarus de tormes, son of tomé gonzález and antona pérez, natives of tejares, village of salamanca. my birth was within the river tormes, by which cause took the nickname, and was thus (this) way. my father, may god forgive me, was in charge of providing a mill of an aceña, which is the bank of that river, in which he was a miller for more than fifteen years; and my mother being one night in the pool, pregnant with me, she took (took) the birth and gave birth to me there: so that i can truly say i was born in the river.

as i was an eight-year-old boy, they blamed my father for some bad bloodshed on the sacks of those who came to grind there, so he was arrested and confessed and did not deny and suffered persecution for justice. i hope in god that he is in glory, because the gospel calls them blessed. at this time a certain armada was made against the moors, among whom my father, who at that time was exiled by the disaster already mentioned, with the charge of an acemilero of a gentleman who went there, and with his master, as a loyal servant, his life.

according to the short introduction you have read, why is it called lázaro de tormes?