According to the later Norse sagas Halfdan was the son of the legendary Viking Ragnar Lodbrok , but the historicity of Ragnar is uncertain .
The identification of Ragnar Lodbrok as the father of son is not to be relied upon .
According to the later Norse sagas Halfdan was the son of the legendary Viking Ragnar Lodbrok , but the historicity of Ragnar is uncertain and the identification of Ragnar as the father of Halfdan is not to be relied upon .