Ollie Pope hit his maiden Test century in the third Test against South Africa, following Ben Stokes to three figures to put England in control at Port Elizabeth.
Stokes dominated the morning session on day two, powering his way to a punishing 120 before leaving the stage to his 22-year-old partner.
Pope went on to 106 not out in a tea total of 426 for eight, reaching his landmark with the 14th boundary of his ninth innings as an international batsman.
Between them, England's middle-order centurions ensured England passed 400 in the first innings of a Test for the first time since December 2017 in Perth.
After a 45-minute rain delay England resumed on their overnight score of 224 for four – a foundation built around slow and steady runs from the top order and a late stand of 76 from Root and Stokes.
Over the course of two one-sided hours England added another 111 without loss, Stokes responsible for 70 of them as he tapped into the kind of groove that very few players have access to.
He started one run behind Pope on 38 but was first to 50, standing tall and twice crashing Kagiso Rabada through midwicket. Pope had already nailed a pleasing square drive and was soon raising his own bat, but made no attempt to match Stokes blow for blow.
Keshav Maharaj, who brought consistency and control throughout day one, was the man in Stokes' sights, slog-swept for six within moments of entering the attack and shipping 12 from his first over.
Stokes saved an even bigger blow for his next visit, clearing the ropes, the grass bank and the ground's perimeter fence in one clean swipe. South Africa could not plug the gaps, with fifth-wicket stand swelling from 100 to 150 at better than a run-a-ball.
The checkpoints kept coming – first England's 300 and then Stokes' 4000th Test run, courtesy of another muscular swipe off Maharaj. On 99 he stroked Dane Paterson for a single and marked his latest memorable moment by removing a glove and bending his middle figure.
That was a nod to his father Ged's amputated digit and a reminder that Stokes senior was watching from a hospital bed in Johannesburg following his admission just before Christmas.
The very next ball saw Pope given lbw off Paterson only for DRS to show the ball missing leg stump, leaving England 335 for four at the interval.
Stokes began the afternoon in top gear but was stopped in his tracks when slashed to backward point, handing Paterson a maiden Test wicket. Having added 203 with Stokes, Pope was now the senior batsman on 79 and the Surrey man calmly marched towards his ton in 190 deliveries.
It came with a sweetly-struck on-drive off Nortje, with Pope taking a second to soak up the moment before embracing Dom Bess at the non-striker's end.
Maharaj chipped off wickets away at the other end, Jos Buttler caught and bowled and Bess held at silly point but Sam Curran left his mark. The all-rounder swung merrily for 44 in 50 balls, striking six fours and a six before being held on the fence.
