Centuries I-V

When the Romans arrived in Toledo in the First Century A.D., they found a "very well-defended city," situated on a mountain and surrounded by a river. The Romans built a massive wall that kept Toledo safe from invasions for centuries and thus left their mark upon this city that had previously been little more than a pre-historic, barbaric settlement on top of a mountain.
Though time and conquerors destroyed most of what Rome left behind, remnants survive.
Columns from the second century grace synagogues that look like mosques, and the layout of Toledo remains distinctly Roman even though the Muslims tried to disguise its origins.
The Alcantara Bridge and El Alcazar.

Here you can see El Rio Tajo (the Tajo River) and El Puente de Alcantara (The Bridge of Alcantara).
This river is perhaps Toledo's greatest defensive player, and for centuries it has kept Toledo isolated and self-sufficient. You can also see here that Toledo is situated on a mountain, another key defensive asset.
This bridge is one of several constructed originally by the Romans.
Though it has been rebuilt several times since the Roman occupation, its lines and structure are preserved.
Perhaps the most famous of Toledo's ancient bridges is El Puente de San Martin (The Bridge of Saint Martin), which is seen in El Greco's Vista de Toledo (View of Toledo).
It is difficult to know much about the Romans from their remains in Toledo because they were either destroyed or assimilated by later cultures. However, we do know that the Romans fancied Toledo a sort of informal royal city (indeed, it is still called "La Ciudad Real" by the more traditional residents of Toledo.
The Visigoths invaded Toledo and expelled the Romans in the Fifth Century A.D. and were the first Christian residents of Toledo.
However, they were all but wiped out by the Muslims and then Christians that followed.