[4] The name of the city was first recorded in chronicles from 1337 in German as Tracken (later also spelt Traken) and is derived from the Lithuanian word trakai (singular: trakas meaning "glade").

Its other alternate names include Тро́кі (Tróki, historic)/Трака́й (Trakáj, modern Belarusian), Trok (Yiddish),[6] Troky, and Traki.

Aukštadvaris Regional Park was founded in 1992 to preserve the valuable landscapes in the upper reaches of Verknė and Strėva.

When Grand Duke Gediminas finally settled in Vilnius, Senieji Trakai was inherited by his son Kęstutis.

Despite the protection, both wooden castles were successfully raided by the Teutonic Knights several times in a row.

The town was in the center of a conflict between Grand Duke Jogaila (later to become King of Poland) with his uncle Kęstutis.

A few weeks later Kęstutis died in captivity and Jogaila transferred the castles to his brother Skirgaila, who became the governor of Lithuania Proper.

However, his rule was briefly interrupted when in 1,383 joint forces of Kęstutis's son Vytautas and the Teutonic Knights captured the town.

Trakai became a political and an administrative centre of the Duchy, sometimes named a de facto capital of Lithuania.

After the Grand Duchy of Lithuania joined the Kingdom of Poland to form the Polish–Lithuanian Commonwealth in 1569, the castles remained a royal property, but the town's importance gradually declined, with the nearby Vilnius and the political center of the Commonwealth in Kraków becoming far more important.

Also Helena, widow of King Alexander was kept there in order to prevent her escape to the Grand Duchy of Moscow.

The works in the Upper castle were almost complete in 1939, when the Invasion of Poland started and the area was soon annexed by the Soviet Union, then by Nazi Germany during Operation Barbarossa.

In 1944, during Operation Tempest, the town was liberated by joint forces of the underground Polish Home Army and Soviet partisans.

After World War II it was again annexed by the Soviet Union and made part of the Lithuanian SSR in the Soviet Union; subsequently many of the city's and area's ethnic Polish inhabitants left for the recovered Territories of the Polish People's Republic.

Today the Island Castle serves as the main tourist attraction, hosting various cultural events such as operas and concerts.

Karaim (or Karaites) are a small Turkic-speaking religious and Jewish ethnic group resettled to Trakai by Grand Duke Vytautas in 1397 and 1398 from Crimea, after one of his successful military campaigns against the Golden Horde.

Despite ever-increasing Polonisation, Trakai remained a notable center of Karaim cultural and religious life.

The local Karaim community, which was the backbone of the town's economy, suffered severely during the Khmelnytsky Uprising and the massacres of 1648.