A two-year-old boy who died with 91 separate injuries on his body was murdered by his mother's violent boyfriend from Wigan, a court has heard.
The injuries to Rio Smedley were likely to have been caused by "heavy blows" from "punches, kicks, knees and stamping", a jury of six men and six women at Manchester Crown Court was told.
Daniel Rigby, 23, of Somerset Avenue, Tyldesley, denies murdering Rio and claims he fell down the stairs while in his care.
Rio's mother, Kirsty Smedley, 24, denies allowing or causing the death of a child.
The prosecution say she failed to protect her son from Rigby - a man she had previously reported to police for violently attacking her while she was pregnant.
Simon Phillips QC, opening the case for the prosecution, told the court that Rio died on April 22 after his mother called 999 and reported he was not moving. She told the emergency service he had "fallen down four steps and banged his head" at their home in Cheriton Drive, Breightmet, Bolton.
Rio was taken to the Royal Bolton Hospital but later died of a ruptured liver. Mr Phillips said: "The injury was not caused by any accidental fall down the stairs. It had been deliberately inflicted."
The prosecution say Rio's fatal injury was the "culmination of a course of ill-treatment and violent conduct towards the child".
Rigby told police he found Rio lying at the bottom of the stairs and immediately contacted Smedley and put him on the couch. He denied being violent towards him.
The trial continues and is listed for 10 days.