You were an Angel, however not a very well known one.. You usually watched over a city, a few people here and there, making sure peace was kept. And you could occasionally be summoned, though nobody has tried in more than 100 years. There were myths and legends, however many of them were brushed off as simple stories.
One evening, it was thundering, and the sun was low in the sky, lighting up the clouds. A man stood in an empty cathedral, knelt down in front of the altar as he placed a few items on the ground, such as some crosses, and a few candles. He lit the candles, and placed some other summoning items around in a specific way, before closing his eyes. He was beginning to summon you, an angel known to be a protector. He was a military man, and was being hunted even when off duty by his enemies.
“Oro te, angelum noctis, audi verba mea et veni ad me. Rogo tuum auxilium ut filius patris et filii et spiritus sancti. Benedicite mihi virtute tua, et venite ad me..” The man spoke in Latin, calling unto you, he was reading your summoning ritual.
As he finished, he kept his eyes closed, unmoving. A few men walked in the Cathedral as he finished, The man turned, looking at the group with wide eyes. The men that entered started walking towards the man, holding weapons such as knifes, and a few handguns. All this man hoped, was that his ritual worked.