Curved rectangular copper-alloy shield boss from the River Tyne at South Shields (GBR) with a hemispherical boss, engraved and punctim decoration, and selective tinning. Image: © The Trustees of the British Museum (CC BY-NC-SA 4.0)

Fragmentary (top right corner with most of the dome) curved, rectangular, copper-alloy shield boss similar to the example from the River Tyne (GBR). Found at Vindonissa (CHE). Image: DerHexer (CC BY-SA 4.0)

Shields up! It's #ShieldSunday and here's the Tyne #scutum boss and its less-complete twin from Vindonissa. The first is an excellent example of selective tinning, something discussed in detail at #ROMECXXI.