The Chapel of Saint Helena (mother of Constantine) is a 12th century Armenian church in the lower level of the Church of the Holy Sepulcher.

After the rediscovery of the Holy Places by Constantine in 326 they immediately became the focus of Christian veneration. Both Calvary (Golgotha) and the Tomb of Christ were isolated by cutting away the surrounding rock and earth, making them free-standing blocks. Between 326 and 337 the Tomb of Christ was surrounded by the so-called Anastasis (Resurrection) Rotunda. Rebuilding occurred in 1048. When the crusaders conquered Jerusalem in 1099 their immediate concern was to restore and beautify the Holy Sepulchre still further, with consecration on 15 July 1149. A church complex now stretches out behind the rotunda. The building was damaged by fire (1808), and then earthquake (1927) and restored in 1962. The Romanesque transepts and ambulatory survive, with the 19th-century choir. The rotunda retains something of its Byzantine appearance, and the Constantinian masonry is visible in its outer walls.