Rome, September 12 - A group of around 40 security guards who face unemployment when their contracts expire at the end of the month scaled Rome's Arch of Constantine on Thursday to protest against their plight. The protestors, who say they have not received their wages for weeks, hung a banner on the ancient Roman monument that read "Work, Rights, Dignity". They are part of a group of 146 workers at the Istituto dell'Urbe security firm who are demanding that the city of Rome respects a commitment it says was made to hire them at a council agency. A group of them staged a similar protest on the Colosseum in 2009. The Arch of Constantine is situated between the Colosseum and the Palatine Hill. It was erected to commemorate Emperor Constantine I's victory at the Battle of Milvian Bridge in 312.