It took two attempts for Rome to even gain a tactical foot hold in Britain. The first of which was in AD 55, by this time Britain was a frequent target for invasions. With just two legions (Legio VII and Legio X), this first attack was unsuccessful, gaining only a beachead on the Kent coast.
It wasn't until AD 43, nearly 100 years after Julius Caesar first attempted invading Britain, that Emperor Claudius sent his army's against Britain and so Roman Britain begun.
The evidence of roman occupation in Hertfordshire is substantial. Roman settlements have been found in many towns including Cheshunt and St Albans.
Runing though Hertfordshire and surround counties are the remains of roman roads. The largest in Herts is Ermine Street. Ermine street ran from London to Lincon to York. A large part of Ermine Street is now the A10 and the A1 formally the A14, once out of Lincon the roman road becomes the A15.
