 Unlike comparable museums in continental Europe , the National Gallery was not formed by nationalising an existing royal or princely art collection . It came into being when the British government bought 38 paintings from the heirs of John Julius Angerstein , an insurance broker and patron of the arts , in 1824 . After that initial purchase the Gallery was shaped mainly by its early directors , notably Sir Charles Lock Eastlake , and by private donations , which comprise two @-@ thirds of the collection . The resulting collection is small in size , compared with many European national galleries , but encyclopaedic in scope ; most major developments in Western painting " from Giotto to Cézanne " are represented with important works . It used to be claimed that this was one of the few national galleries that had all its works on permanent exhibition , but this is no longer the case . 
