The Story is about Arthur & Guinevere, that's me pre Death & Resurrection & Cara's Intruder. Fanciful Stories & Costumes were Heavy Jock Fabric & Skirts, not White Linen & Princely Armour for every Roman Soldier.
Cleo: Egyptian Blue is Woad of Common Local Chalk & Flowers made Solid.
Ancient things cannot be compared to Modern refined things usually, Concrete was indistinguishable. I have Tiny Chestnuts in the Valley & small Flowerheads on the Hill. Early attempts at reinforced Concrete had a Bronze sheet nailed around a Log & Molten Metal Mix. Concrete stayed intact over 1000 years below the Surface.