Lucas de Tuy or el Tudense (died 1249) was a Leonese cleric and intellectual, remembered best as a historian. He was Bishop of Tuy from 1239 until his death. Born in León, Lucas was a canon of San Isidoro there between 1221 and 1239. While a canon he wrote De Miraculis Sancti Isidori in defence of Isidore of Seville. He also travelled extensively: to Rome, Constantinople, Cyprus, Jerusalem, Armenia, and France.
M81 or M-81 may refer to: M-81 highway (Michigan), a road in the United States of America McDonnell-Douglas MD81 Messier 81, a spiral galaxy in the constellation Ursa Major, also known as NGC 3031 or Bode's Galaxy