People of the Urnfield culture were living in Zagreb by 1300 BCE and were affected by the migrations of the Bronze Age collapse.
In 12th or 11th century BCE they built a likely fortified settlement at the location of modern-day Priest's Tower (Popov toranj) and Demeter Street.
Old Zagreb consisted of two settlements on neighboring hills - Gradec (also known as Gornji Grad) and Kaptol - and the houses in the valley between them along the former Medveščak creek (present-day Tkalčićeva Street).
The foundation of Kaptol (on the eastern slope) is traditionally dated in 1094, when Ladislaus I of Hungary founded the Zagreb diocese during the War of Croatian Succession.
During Hundred Years' Croatian-Ottoman War, in preparation for a possible Turkish attack, the bishop of Zagreb had fortifications built around the cathedral and his residence.
The defensive towers and walls built between 1512 and 1520 still stand today, except those facing the front of the cathedral in Kaptol Square (which were demolished in 1907).
The defensive walls enclosed the settlement in the shape of a triangle, with its apex near the Popov Toranj tower and its base at the south end (the Strossmayer Promenade).
When guilds developed from the 15th to the 17th centuries as societies of craftsmen, their members (masters, journeymen and apprentices) gathered regularly at St. Mark's.
In the old part of present-day Vlaška Street, below the archbishop's residence and gardens, is a row of houses built from the end of the 18th to the beginning of the 19th centuries along the old road.
For one, Kaptol aimed to collect rents (mitnica and placovina) on entire territory of Zagreb, including Gradec, as kings granted them these rights.
On the same day, Kaptol servants attacked Nova Ves na Savi, where they allegedly raped women and killed some rich serf in his own house.
On New Year's Eve, residents of Kaptol even dug out the graves of citizens of Gradec who were buried after excommunication and desecrated their remains.
CItizens of Gradec contributed to Hungarian troops in 1526 Battle of Mohacs by sending 40 well armed infantrymen and six horses used for towing cannons.
The building and decoration of the church interior were incentives for local carpenters, sculptors, painters and gilders who were developing their own Baroque style.
In addition to new elements introduced to the old city, it was realized that the relatively-small squares around St. Mark's Church and in front of the cathedral were unsuitable for large fairs.
The new marketplace and fairgrounds became places to conduct business, encouraging the authorities to develop the outskirts of the city and build access roads.
The market place and fairgrounds at Manduševac attracted people from south of the city and, by the middle of the 18th century, saw the beginnings of present-day Petrinjska Street.
A ferry or pontoon bridge linked Zagreb and the area across the river, which was important to supply the Military Frontier.
At the beginning of the 17th century, when Turkish raids across the Sava were no longer a threat, city authorities established serfs' villages in the vicinity.
Gračani, Gornje and Donje Prekrižje, Jelenovec, Vrhovci, Čukovici, and Domjanići were on the mountain, and on the plain near the river were Trnje, Ilijašići, Bankoviti and Govenka (which no longer exists), Horvati and Črnomerec.
This urban area, stretching from Medvednica to the Sava, appears on a large-scale map drawn by surveyor Leopold Kneidinger in 1766 which is in the Zagreb City Museum.
Modern architecture, led by Viktor Kovačić, is exemplified by St. Blaž Church at the corner of Deželić Drive and Primorska Street.
Zagrebacki Zbor, the forerunner of the Zagreb Fair, organised its shows and displays at the riding school in present-day Martićeva Street, and the Burza area was the fairgrounds.
The interwar period saw the area's development, with Kovačić's 1925–1926 stock-exchange buildings at 3 Burza Square, Ivan Meštrović's round exhibition pavilion (the present Croatian History Museum) and the Đuro Salaj Hall.
Building flourished during the decade, since Zagreb was an industrial and business centre with a population of about 280,000 before World War II.
The railways enabled the old suburbs to gradually merge into Donji Grad, characterized by the block pattern prevalent in Central European cities.
Working-class housing increased between the railway and the Sava, and residential construction on the southern slope of Medvednica was completed between the two World Wars.
Urbanized lines of settlements connect Zagreb with its surroundings: Sesvete, Zaprešić, Samobor, Dugo Selo and Velika Gorica.
On March 22, 2020, a strong earthquake hit Zagreb, causing significant damage to the historic downtown area.
In the early hours of Friday, 11th of March 2022, an unidentified aircraft crashed into the Jarun district near a student home, causing moderate property damage.