<Table> <Tr> <Td> Impressionist </Td> <Td> c. 1875--1925 </Td> </Tr> <Tr> <Td> <Ul> <Li> Modern </Li> <Li> High modern </Li> </Ul> </Td> <Td> c. 1890--1975 </Td> </Tr> <Tr> <Td> 20th century </Td> <Td> (1900--2000) </Td> </Tr> <Tr> <Td> <Ul> <Li> Contemporary </Li> <Li> Postmodern </Li> </Ul> </Td> <Td> c. 1975--present </Td> </Tr> <Tr> <Td> 21st century </Td> <Td> (2000--present) </Td> </Tr> </Table> <Tr> <Td> Impressionist </Td> <Td> c. 1875--1925 </Td> </Tr> <Tr> <Td> <Ul> <Li> Modern </Li> <Li> High modern </Li> </Ul> </Td> <Td> c. 1890--1975 </Td> </Tr> <Ul> <Li> Modern </Li> <Li> High modern </Li> </Ul>

One of the most significant changes in the minds of composers in the twentieth century was that