I think that you have heard speaking about Qumran scrolls discovered in the forties and fifties of last century. Not far from the Dead Sea shore archaeologists discovered a lot of scrolls written in hebrew, greek and even in latin and hidden inside pottery jars. Most of them were biblical texts, but have been discovered also apocriphal books unknown before. These texts were written by men and women that lived in a very special settlement located on a barren terrace between the limestone cliffs of the Judean desert and the maritime bed along the Dead Sea.
The site was the wilderness retreat of the Essenes, a separatist Jewish sect of the Second Temple Period, a portion of whom had formed an ascetic monastic community. The sectarians inhabited neighboring locations, most likely caves, tents, and solid structures, but depended on the center for communal facilities such as stores of food and water. The Essene community wrote, copied, or collected the scrolls at Qumran and deposited them in the caves of the adjacent hills. Some scholars believe that the scrolls were hidden in the caves to protect them from the invading Romans during the military campaign of the 68 CE.
In February, 1955, archeologists (under the direction of the late Father Roland de Vaux) discovered the cave number 7. Its content consisted of several Creek papyrus fragments, subsequently numbered 1 to 19, among which the famous 7Q5 identified by José O’Callaghan as text of Mark’s Gospel and dated at 50 CE. Inside the cave were discovered also a few pottery vessels, including three jars. One of them bears the twice repeated Hebrew letters [in transcription] rwm’. It could be an attempt to write Rome in Hebrew letters, and Rome is the christian community to which the Gospel of Mark may have been addressed. If so inside the jar may have been hidden a scroll or scrolls of the Gospel of Mark, because the Essene community was very interested in investigating the time and charateristics of the future Messiah, and Messiah’s identity is the main topic of Gospel of Mark.
Many scholars believe instead it would be better read the inscription as a proper name of some individual that posessed the jar. But why this jar was inside a cave where sectarian movement concealed their manuscripts? Could one of the segregated Essenes have bought in a marketplace somewhere in Palestine a jar possessed by a certain Rwm? In my opnion the best hypothesis is that the Essenes had a copy or copies of Gospel of Mark and that they concealed it, along with other christian texts, inside a jar that was sealed and inscribed with the hebrew letters that indicated the provenance: Rome.
Suggested reading: Carsten Peter Thiede, Rekindling the word, 1995