Henry Syer Cuming (1817 to 1902) continued his father's work of collecting things from the everyday lives of people all over the world, but his special interests were the archaeology of London, folklore and British popular art and the lives of the people of South London. He collected many thousands of objects that revealed the ordinary lives of South Londoners in the 1800s, from theatre adverts and rail tickets to cheap toys and good luck charms.

During Henry's lifetime the growing antiques market was flooded with fakes which Henry enjoyed collecting and exposing.

When he died in 1902 he left the Cuming family collection to the people of the parish of St Mary Newington (now the Borough of Southwark). His will stated "My museum illustrative of natural history, archaeology and ethnology with my coins and medals and along with all other curios" be exhibited in "a suitable and spacious gallery or apartments in connection with Newington Public Library."

The museum was to be known as the Cuming Museum and he left a sum of money to employ a curator. The museum was opened in 1906 by Lord Rothschild.