There is evidence Sinj has been inhabited since prehistoric times. A number of archaeological finds from the Copper age through to the Bronze Age are attributed to the so-called Cetina culture.
After the fall of the Roman Empire in the 7th century, Sinj was inhabited by Croats, who practised Christianity and created a strong military presence. Frequent Turkish attacks led to the fall of the Cetina district and the town of Sinj in 1523 where they held it until 1686 when it was fell under Venetian rule.
The Turks however, were not ones to give up easily. They continued to try and conquer Sinj, but the people of Sinj were resilient and passionate, willing to give their life for their town. In 1715, the Turks attacked Sinj for a final time. The Turkish army heavily outnumbered the Sinj defenders, who stood at only 700 compared to tens of thousands of Turks. Fighting bravely and never giving up, the Sinj soldiers won the battles as the Turks, weakened by hunger and disease, left the Cetina region. The Sinj dedicated their win to Our Lady Mary and deemed it Gods deed for them to win.
The Venetians once again occupied Sinj until 1797, where Austria took leadership. Although there was a brief period of French ruling, Austria soon ruled Sinj again until 1918. Sinj, as part of the Cetina district, has always been a town of national pride and belonging to Croatia. They have often fought for Croatian language and uniting Croatia which is why it was so celebrated when they became part of the Republic of Croatia in 1992.