The first fortifications founded a ruler Mazovia most likely already in the eleventh century, a stone castle built in 1433 years voivode of Trakai and Vilnius John Gosztołd, known to participate in the Battle of Grunwald, where he commanded a division of Lithuanian. It was built on an irregular quadrangle, the wall of the south-east was a residential building. For 1542 years it belonged to the family of Gosztołdów, and after the death of the last of their representatives passed into the hands of King Sigismund the Old and Sigismund Augustus after him.

At his command began to expand Tykocin. When it was built new residential house - Renaissance and several outbuildings with defensive walls but outside the castle. Some of them took the crew of the castle. King Sigismund Augustus personally oversaw the work during his numerous stays in Tykocin.

In terms of the defense of the castle was one of the strongest fortresses in Poland. Caused a marshy area, among which the enemy had great difficulty finding the artillery positions. The whole wood-reinforced earthworks and moats, cuttings and palisades. At the corners of the quadrilateral assumptions were four cylindrical towers, and one of the wings of entry defended the gate tower. It is here that the last of the Jagiellonian dynasty has placed his treasure and a rich collection of books brought from Vilnius.

After the death of Sigismund Augustus was buried in the Wawel Castle, the castle remained Tykocin and his treasures. He received them with hand heir of Augustus, Queen Anne's, and the crown of Polish King Stefan Batory. This king also appreciated Tykocińską say, but give a higher priority to the defense of the castle than Zygmunt August. It's his order was in Tykocinie royal arsenal. According to the estimates of historians there were 500 guns and large quantities of small arms and ammunition.

At the beginning of the seventeenth century., Towards the development of artillery, around the castle walls built bastion fortifications. Four earth bastions of internal reinforcing wooden structures, combined with curtains, covered an area of ​​over 6 acres, the length of the sides was 250 m.

Bridge which is the only one coming to defend the castle on the opposite side of the river Seminary, where during quiet resided wysłużeni officers. Places Studentate admitted hetman officers do not have a means of livelihood.

In the seventeenth century Tykocin widely regarded as one of the most powerful fortresses in lowland Europe. Siege of Tykocin during the Swedish invasion Sienkiewicz described in his "Trilogy", also preserved an authentic relationship to participate in those fights. During the attack on the besieged fortress commanding the army Janusz Radziwill Paul Sapieha szturmującym gave permission robbery after the capture of the castle, which was a common practice at the time. This procedure resulted in greater zeal branches counting on a big payoff.

Although unprepared Sapieha artillery commanded to storm the walls, using the aura that froze the moat. Surprised by this turn of events forces Radziwill was able to defend only a few hours, and then determined the Swedes blew up two towers of the castle gatehouse suffering and death. They preferred her from getting into the hands furiously attacking the Polish-Lithuanian army.

Tykocin was taken on January 27, 1656., And revived the trade route between the Polish and Lithuanian. After the war, as a reward castle got Stefan Czarnecki, who rebuilt it. Fortress still served as an arsenal, later the castle passed into the hands Branickis. During the Great Northern War took place in the 1705 meeting of the Polish king Augustus II of Tsar Peter I. It was inhabited 1734 years yet, then partially burned and fell into disrepair.

Since the mid-eighteenth century, local residents began the demolition of the castle, using the building material for the construction of new homes in Tykocin. Flood 1771 settled the fate of the surviving remnants of buildings. In 1915, the Germans used stones and bricks from the rubble to build and repair roads, and the land of the two bastions took to usypywania dike.

Today, in place of the mighty fortress can be seen only small fragments of earthen fortifications, and the outline of the castle walls, you can just read the plan of ancient buildings. In good condition, but after numerous reconstructions, survived przedmościa fortified castle - building the seminary.