Tuesday is a day of the week occurring after Monday and before Wednesday. According to some commonly used calendars (esp. in the US), it is the third day of the week. According to international standard ISO 8601, however, it is the second day of the week. The English name is derived from Old English Tiwesdæg and Middle English Tewesday, meaning "Tīw's Day", the day of Tiw or Týr, the god of single combat, victory and heroic glory in Norse mythology. Tiw was equated with Mars in the interpretatio germanica, and the name of the day is a translation of Latin dies Martis. The name Tuesday derives from the Old English "Tiwesdæg" and literally means "Tiw's Day". Tiw is the Old English form of the Proto-Germanic god *Tîwaz, or Týr in Norse, a god of war and law.