The gens Ulpia was a Roman family that rose to prominence during the first century AD.
[3] The most illustrious members of this gens were the Ulpii Trajani, whom according to a biographer of Trajan, came from the city of Tuder, in southern Umbria; there is evidence of a family of this name there.
Members of this family were colonists of Italica in Roman Spain, where Trajan was born.
They were related to a family of the Aelii, which had evidently come from Atria; Trajan's aunt was the grandmother of Hadrian, who was likewise born at Italica.
Trajanus indicates descent from or relation to the gens Traia, a family also known to have been present in Hispania.