AD 142

Year 142 (CXLII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known in the Roman Empire as the Year of the Consulship of Pactumeius and Quadratus (or, less frequently, year 895 Ab urbe condita). The denomination 142 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Roman Empire

 * Emperor Antoninus Pius orders the construction of the Antonine Wall. The wall stretches 39 miles (63 km), from Old Kilpatrick in West Dunbartonshire on the Firth of Clyde, to Carriden near Bo'ness on the Firth of Forth (Scotland). The Romans build 19 forts and smaller fortlets (milecastles), to protect the border against the Caledonians.
 * Municipal doctors are named throughout the Roman Empire.

Asia

 * First year of the Hanan era of the Chinese Han Dynasty.
 * The Chinese Taoist alchemist Wei Boyang, author of the Kinship of the Three, is the first to describe an early form of gunpowder solution.

Religion

 * Marcion proclaims that the Old Testament is incompatible with Christianity.

Births

 * Papinian, Roman jurist and praetorian prefect (d. 212)
 * Elpinice, Roman noblewoman (d. 165)
 * Liu Biao, Chinese governor (d. 208)

Deaths

 * Hyginus, bishop of Rome (approximate date)