Complex sentence: With the coming of the Great Northern Railway in 1868 the area began to emerge, and property was built gradually between the 1870s and the 1930s however it wasn't until 1914 that a more recognisable East Finchley High Road and surrounding area was visible.
Split into simpler sentences: With the coming of the Great Northern Railway in 1868 the area began to emerge, and property was built gradually between the 1870s and the 1930s. However, it was not until 1914 that a more recognisable East Finchley High Road and surrounding area was visible.