The rivalry between Melbourne and Sydney has a long history.
Everything from the weather to the football is keenly debated.
But one thing remains a fact - Sydney is Australia's largest city, with a 2018 population of 5.23 million.
But has it always been this way, and what of the future?
Read on the find out more.
Melbourne was the largest city in the second half of the 19th century
Although Sydney was established well before Melbourne, the 1850s Gold Rush had a considerable impact on population growth due to a steep rise in overseas and interstate migration.
By the early 1860s, Melbourne's population exceeded Sydney's, and it remained this way until the end of the 19th century.
In 1901, Melbourne was still Australia's largest city, with a population of 501,580.
However, the city had been hit hard by the 1890s recession, slowing population growth.
By 1906, Sydney had regained the title of Australia's largest city, with a population of 559,800.
Population growth in the 20th century
The ABS recently updated their the historic demographic datasets which is a valuable resource for researchers.
Annual population data is available from 1920, and the chart below shows the population of Sydney and Melbourne since that time.
The geography may have changed, particularly as the cities have grown outward, but the data still provides a valid point of comparison.
Note that there are several series breaks in this data, more information is available from the ABS in the link provided above.
Sydney's population hit 1 million in 1926, and 2 million in 1958.
Melbourne hit these milestones a little later.
The population reached 1 million in 1929 but then declined for the next three years.
The population did not reach 1 million again until 1934, and then grew further to reach 2 million in 1962.
During the 20th century, population growth was strongest in the 1950s and 1960s. Melbourne also recorded stronger growth than Sydney during these decades.
The stronger population growth was a result of higher fertility rates and high levels of overseas migration.
It's worth pointing out that the growth rates recorded in both cities in these decades were stronger than those recorded now, but the volume of growth was lower.
Nevertheless, the impact of rapid growth at the time presented significant urban planning challenges, particularly with regard to infrastructure provision (sound familiar?).
For example, there was a significant backlog in sewerage connections in Sydney that persisted until the 1970s.
Population growth in both cities declined in the 1970s and 1980s, due to a combination of factors including declining fertility and migration, tightening economic conditions, and economic restructuring in the manufacturing sector.
This impacted on Melbourne more than Sydney due to the larger workforce in this sector, and in some ways continues to this day.
Sydney's population reached 3 million in 1971, with Melbourne following in 1987.
The early 1990s economic recession hit hard in Melbourne, exacerbated by further job losses in manufacturing as well as crises in the banking sector.
Net interstate migration losses reached more than 30,000 in 1994.
Between 1990 and 2000 the population of Melbourne grew by 286,490 compared to 398,970 in Sydney.
At the turn of the century, Sydney had a population of 4.04 million, compared to 3.45 million in Melbourne.
The 21st century and beyond
The demographic story of both cities is more volatile.
Since 2006 population growth in Australia has increased, influenced by the mining boom and the expansion of the higher education sector.
Melbourne had well and truly recovered from the early 1990s recession, and as a state, Victoria was gaining population from other parts of Australia for the first time in many decades.
Since 2002, Melbourne has recorded a higher population growth rate than Sydney.
This has resulted in the population of Australia's two largest cities converging.
In 2001, the difference in population reached its peak, at 602,330.
Ten years later, the difference was 439,580, and at June 2018 had further converged to 266,980.
The stronger growth in Melbourne has seen some commentators suggest that Melbourne will become Australia's largest city in the near future.
These analyses tend to be based on the current volume of growth and extrapolated forward, which is a very simplistic way of forecasting population growth as it doesn't consider the volatility of net overseas migration in particular.
More recent population projections released by the ABS indicates that under a high growth scenario, Melbourne will become Australia's largest city in 2032.
These projections consider all components of population change rather than just adding the volume of growth each year.
But regardless of whether Melbourne or Sydney is larger, both cities still face significant urban planning challenges.
It's not so much about the numbers, but more about how the population is changing, how this impacts demands for services, how we travel around, and our liveability.
Summary
SummarySydney and Melbourne are Australia's two largest cities.
Melbourne had the largest population for most of the second half of the 19th century, but Sydney regained the title in 1906.
Sydney's population reached 1 million in 1926, 3 million in 1971 and in 2018 stood at 5.2 million.
Melbourne's population stabilised at 1 million in 1934 and reached 3 million in 1987 and in 2018 stood at just under 5 million.
Melbourne has recorded stronger growth during the 21st century.
Population projections produced by the ABS using a high growth scenario indicate Melbourne will become Australia's largest city in 2032.
