The Romans chose Leicester to be one of their cities. Why did they choose Leicester? Why not choose Glenfield, or Groby? The Romans made this decision based on the things that a Roman town needed; and on strategic positioning
Water. Everyone needed water, and there are a ready supply from the River Soar.
River Crossing. The river crossing on the Soar was at Leicester. It was one of the only places to cross, and therefore anyone wanting to cross the Soar would have to come through Leicester ..... perfect for what we call today "customs control".
Transport. Just out side of Leicester is High Cross, the literal centre of Roman England (the furthest point from any coast or border). Two major Roman roads crossed here: the Fosse Way and Watling Street. The Fosse Way itself went directly through Leicester, and therefore made it very easy to get to any area of the country using these two roads.
Natives. Before the Roman annexation, the Celtic tribe of the Coritani has their capital here. The Romans are suppose to be great fighters, never loosing a battle. The truth actually is that they knew that the best way to annex a country was not fighting but making the Britons feel secure. They did this by placing one of their major cities on the site of one the Celtic capitals; making the Britons feel that their city is important.