The fanlight window is the quinessential feature of the Georgian terrace house. They were the overdoor solution to getting light into a hallway when the house was part of a terace. They are celebrated in cities such as Bath, Edinburgh, Cheltenham, London and Dublin. With repeated Georgian houses ariving in long terraces in an age before street numbering had been introduced it is thought the differing patterns along the terrace allowed for differentiation. They sometimes incorporated lanterns - the central circle would normally line up with lanterns both in the portico or inside in the hallway.