Ledesma still has most of the granite wall which historically has surrounded the town. A large part of what is still standing was built in times of Fernando II of Leon, in the 12th century, but in the 15th century several parts of it were rebuilt with well-carved masonry. Many stone mason marks can be seen among these stones. Out of the eight doors it once had, the only one that is still preserved is the one called Puerta de los Mártires, de San Nicolás or Caldereros (Martyrs’, San Nicolás or Boilermakers’ door). Formed by two camber arches, it is flanked on either side by two cylinder towers.
The bailey of this castle-fortress was built on the south-west end of the walled area between the 13th and 14th centuries. Set on an irregular trapezoidal plan, it has two doors: one on the north, which features the town’s coat of arms, and one on the south, flanked by two large towers.References:
The Arch of Constantine is situated between the Colosseum and the Palatine Hill. It was erected by the Roman Senate to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge in 312. Dedicated in 315, it is the largest Roman triumphal arch. The arch spans the Via triumphalis, the way taken by the emperors when they entered the city in triumph.
Though dedicated to Constantine, much of the decorative material incorporated earlier work from the time of the emperors Trajan (98-117), Hadrian (117-138) and Marcus Aurelius (161-180), and is thus a collage. The last of the existing triumphal arches in Rome, it is also the only one to make extensive use of spolia, reusing several major reliefs from 2nd century imperial monuments, which give a striking and famous stylistic contrast to the sculpture newly created for the arch.
The arch is 21 m high, 25.9 m wide and 7.4 m deep. Above the archways is placed the attic, composed of brickwork reveted (faced) with marble. A staircase within the arch is entered from a door at some height from the ground, on the west side, facing the Palatine Hill. The general design with a main part structured by detached columns and an attic with the main inscription above is modelled after the example of the Arch of Septimius Severus on the Roman Forum.