and long limbs. In 122 AD construction began on Hadrian's Wall, creating a physical boundary between Roman controlled territory, and the land the Romans deemed as Caledonia. An effort by the Romans to invade and conquer Caledonia was likely made sometime during or shortly after 139 AD. In 142 AD, construction began on the Antonine Wall roughly 100 km North of Hadrian's Wall in order to aid in the Roman push into Caledonian territory and to consolidate their conquest of southern Caledonian territory. The Romans later abandoned this wall (around 158) to return to Hadrian's Wall to the south. According to Malcolm Todd, the tribes of what is now Northern Britain and Scotland (probably including the Caledones) proved themselves to be "... too warlike to be easily contained...", leading to the extensive garrisons left by the Romans to contest the tribes. Fraser and Mason argue that the Caledones likely did not directly attack or harass the Romans during this time, but may have had minor conflicts with other tribes. In AD 180 the Caledonians took part in an invasion of Britannia, breached Hadrian's Wall and were not brought under control for several years, eventually signing peace treaties with the governor Ulpius Marcellus. This suggests that they were capable of making formal agreements in unison despite supposedly having many different chieftains. However, Roman historians used the word "Caledonius" not only to refer to the Caledones themselves, but also to any of the other tribes (both Pictish or Brythonic) living north of Hadrian's Wall, and it is uncertain whether these later were limited to individual groups or wider unions of tribes. It is possible that this was the peoples of Brigantia rather than the Calidones. By the latter half of the 2nd Century AD, the actual Caledones would have likely had the Maeatae peoples between themselves and the Antonine Wall. During the reign of Commodus, a series of regular payments appear to have been made to the Caledonians by the Romans, continuing into the first few years of Severus' reign, according to John Casey. In 197 AD Dio Cassius records that the Caledonians aided in a further attack on the Roman frontier being led by the Maeatae and the Brigantes and probably inspired by the removal of garrisons on Hadrian's Wall by Clodius Albinus. He says the Caledonians broke the treaties they had made with Marcellus a few years earlier (Dio lxxvii,