text: The family includes his brother Kartikeya. Regional differences dictate the order of their births. In North India, Skanda is generally said to be the elder brother while in the South, Ganesha is considered the first born. Prior to the emergence of Ganesha, Skanda was an important martial deity from about 500 BCE to about 600 CE, when his worship declined significantly in North India. The period of this decline is concurrent with the rise of Ganesha. Several stories relate episodes of sibling rivalry between Ganesha and Skanda and may reflect historical tensions between the respective sects.
  Once there was a competition between Ganesha and his brother to see who could circumambulate the three worlds faster and hence win the fruit of knowledge. Skanda went off on a journey to cover the three worlds while Ganesha simply circumambulated his parents. When asked why he did so, he answered that his parents Shiva and Parvati constituted the three worlds and was thus given the fruit of knowledge.
  In his survey of Ganesha's rise to prominence in Sanskrit literature, Ludo Rocher notes that:
  Above all, one cannot help being struck by the fact that the numerous stories surrounding  concentrate on an unexpectedly limited number of incidents. These incidents are mainly three: his birth and parenthood, his elephant head, and his single tusk. Other incidents are touched on in the texts, but to a far lesser extent.