In addition to being awarded as an earned degree, this doctorate is also widely conferred "honoris causa" to recognize one's lifetime of excellence in a particular humanistic, cultural, or artistic field, or other notable contributions to society. When conferred as an honorary doctorate, many or all of the standard degree requirements, including application, matriculation, coursework, doctoral dissertation or thesis, and portfolio evaluation may be waived, at the discretion of the degree-granting body. Honorary Doctor of Letters recipients do not necessarily have any previous affiliation with the awarding institution and, in most cases, it is not considered proper for them to use the title of "Dr." before their names. Universities, colleges, or learned bodies may award the honorary degree of Doctor of Letters, or the related Doctor of Humane Letters, to luminaries who have been identified as rare exemplars who have enriched the humanities in particular, or humanity at large. Mark Twain was awarded an honorary D.Litt. by Oxford University in 1907 for his literary contributions.