Roman and Saxon remains have been found in the Fordcroft area. An excavation in 1960 was conducted by members of Bromley Museum in Orpington. Members of the Orpington and District Archaeological Society (ODAS) have excavated further sites that have become available.

St Mary Cray developed into a market town. The privilege of holding a market on Wednesdays was granted by Edward I (1272 - 1307) f

The district being an agricultural one, the small population worked on its many fruit farms and hopfields.

The most famous of the early industries were the 17th-century foundries of Hodson and Hull where several famous bells were cast. Christopher Hodson made bells for Canterbury Cathedral and Oxford.

The advent of the Industrial Revolution saw brewing and paper manufacturing grow into principal industries beside the River Cray. Three mills are mentioned in Domesday (1087). From the early 1800s until the Depression in the 1930s, many local workers were employed at the Joynson and the William Nash paper mills.

With the expansion of the railways, the population increased rapidly. The building of the railway viaduct across the Cray Valley is considered to be the origin in 1860 of Cray Wanderers F.C. who are London’s oldest association football club. Migrant workers came to the district to help construct the giant earth embankments for what became the London, Chatham & Dover Railway. Games of football started at Star Lane, today the site of a cemetery.

In the 1930s the farmlands of Poverest on the west side of the river were turned over to the construction of industrial and office buildings. The factories along Cray Avenue were engaged in industries ranging from paint and ink manufacture to baking and preserved foods.