A paramedic is a healthcare professional that works in emergency medical situations. Paramedics provide advanced levels of care for medical emergencies and trauma. The majority of paramedics are based in the field in ambulances, emergency response vehicles, or in specialist mobile units such as cycle response. Paramedics provide out-of-hospital treatment and some diagnostic services although some may undertake hospital-based roles, such as in the treatment of injuries.Throughout the evolution of paramedic care, there has been an ongoing association with military conflict. One of the first indications of a formal process for managing injured people dates from the Imperial Legions of Rome, where aging Centurions, no longer able to fight, were given the task of organizing the removal of the wounded from the battlefield and providing some form of care. Such individuals, although not physicians, were probably among the world's earliest surgeons by default, being required to suture wounds and complete amputations.