When you look at maps of London over time Lincoln’s Inn Fields is one of the few constant green spots. Here’s a map from 1682 I stumbled across in the 1911 Survey of London.
In the early C17th there had been much wrangling to protect the Fields from commercial property development. This was interrupted by the civil war and by the late 1600s the Fields had established a shape that is familiar over 300 years later.
Friends of Lincoln's Inn Fields 