According to an old legend, the present-day territory of Tbilisi was covered by forests as late as 458. One widely accepted variant of the legend of Tbilisi's founding states that King Vakhtang I Gorgasali of Georgia went hunting in the heavily wooded region with a falcon (sometimes the falcon is replaced with either a hawk or other small birds of prey in the legend). The King's falcon allegedly caught or injured a pheasant during the hunt, after which both birds fell into a nearby hot spring and died from burns. King Vakhtang became so impressed with the hot springs that he decided to cut down the forest and build a city on the location. The name Tbilisi derives from the Old Georgian word "Tpili" (თბილი), meaning warm. The name 'Tbili' or 'Tbilisi' ('warm location') was therefore given to the city because of the area's numerous sulphuric hot springs that came out of the ground.
Archaeological studies of the region have revealed that the territory of Tbilisi was settled by humans as early as the 4th millennium BCE. The earliest actual (recorded) accounts of settlement of the location come from the second half of the 4th century CE, when a fortress was built during King Varaz-Bakur's reign. Towards the end of the 4th century the fortress fell into the hands of the Persians after which the location fell back into the hands of the Kings of Kartli (Georgia) by the middle of the 5th century. King Vakhtang I Gorgasali (reigned in the middle and latter part of the 5th century), who is largely credited for founding Tbilisi, was actually responsible for reviving and building up the city and not founding it. The present-day location of the area which Gorgasali seems to have built up is spread out around the Metekhi cliff and the latter-day Abanotubani neighbourhood.
King Dachi I Ujarmeli, who was the successor of Vakhtang I Gorgasali, moved the capital from Mtskheta to Tbilisi according to the will left by his father. It must be mentioned that Tbilisi was not the capital of a unified Georgian state at that time (therefore did not include the territory of Colchis) and was only the capital of Eastern Georgia/Iberia. During his reign, King Dachi I was also responsible for finishing the construction of the fortress wall that lined the city's new boundaries. Beginning from the 6th century, Tbilisi started to grow at a steady pace due to the region's favourable and strategic location which placed the city along important trade and travel routes between Europe and Asia.