Short answers, pulled from the story.
According to the Martyrdom of Arethas, Najran derives from a Hebrew term meaning both "thundering city" and "invincible lock." The scholar Christian J. Robin clarifies that the ancient oasis was called both Najran and Rgmt, with Rgmt deriving from the Hebrew Ra'ma meaning "thundering city," while the Arabic najran means "invincible lock," a reference to Najran's role as the gateway to Yemen.
In 523 AD, the Jewish Himyarite king Dhu Nuwas dispatched his general Sharahil Yaqbul dhu-Yazan to besiege Najran. After a thirteen-month siege, Najran fell, and three inscriptions record the execution of 12,500 people. Dhu Nuwas had reportedly sworn on a Torah scroll to guarantee the Christians' safety, then broke his oath. The massacre generated major works of Christian literature, including the Book of the Himyarites and the Greek Martyrdom of Arethas.
Christianity may have been introduced into Najran around 450 AD, likely through trade routes. The Chronicle of Seert attributes the conversion to a merchant named Hannan who traveled to Constantinople and Al-Hira before returning to share his new faith. Explicitly Christian inscriptions survive at the nearby Hima Paleo-Arabic site, with texts dating from the late fourth to early fifth centuries.
Saudi Arabia captured Najran during the Saudi-Yemen war, launched on the 20th of March 1934 following failed negotiations in February of that year. The conflict ended with the Treaty of Taif, signed on the 20th of May 1934. Saudi Arabia initially claimed only temporary rule over Najran Province, but asserted permanent ownership in 1994.
The Ismailis are the primary religious community in Najran, a branch of Shia Islam with historical roots in the province. Saudi Arabia's official discrimination against them encompasses government employment, religious practice, and the justice system. A major confrontation occurred on the 23rd of April 2000 outside Najran's Holiday Inn, where two Ismailis were killed after security forces arrested an Ismaili cleric and the governor refused to meet demonstrators.
Al-Okhdood is the site of ancient Najran, located south-east of the present-day city. The old city was surrounded by a circular wall measuring 220 by 230 meters, built of square stone with defensive balconies. Excavations there have uncovered glass, metals, pottery, and bronze artifacts, including a bronze lion head on display at the local museum.