Here is a montage of old Athens, from 1845, with mount Hymetus in the distance. The hill in the center is the current site of the marble stadium, build for the 1896 Olympic games and still in use today. You can see the columns on the right (a couple have fell since), Hadrian's arch on the left and very few houses.
This is a view from 1845, when Athens was independent from Turkish rule, and when it was established as the Capital (Nafplion in the Peloponese was modern Greece's first capital city). The houses you see on the side of the Acropolis were those of the workers who were involved in building most of Athens, many of them coming from the Kyklades islands.
Shades of modern Athens appear around 1862 when houses start being build out of town (at Eksarhia).
Around 1870, this is the view from the Acropolis, looking towards the city. You can see the Temple of Hefestus on the left, small houses in Plaka, a lot of empty space which became parks and Omonia Square and in the distance, clean air, olive groves and empty mountains.