Coat of Arms. Olyka Castle – A principal seat of the Nesvizh-Kletsk-Olyka line, its construction was initiated by Mikołaj "the Black" and inherited by his son, Stanisław "the Pious". It was expanded in the 18th century. However, due to Dominik Hieronim's involvement in the Napoleonic army, the Russian government confiscated the castle from the family, together with Nieśwież. Antoni Radziwiłł received it in 1815. In the late 19th century, it was also renovated by his grandchildren. Mir Castle Complex – A Gothic style castle that passed into the hands of Mikołaj Krzysztof "the Orphan" in 1568, it was finished in the Renaissance style. The Swedes destroyed the complex in 1655 and 1706. After being rebuilt, Karol Stanisław "Panie Kochanku" took up residence. The castle suffered severe damage during the Napoleonic period and was uninhabited for nearly a century before being restored again at the end of the 19th century. In 1813, after the death of Dominik Hieronim, the castle and its enormous estates were inherited by his daughter, Stefania, who married Ludwig zu Sayn-Wittgenstein-Berleburg. The castle then passed to her daughter Mary Sayn-Wittgenstein-Sayn, wife of German chancellor Chlodwig, Prince of Hohenlohe-Schillingsfürst, who was forced to sell it as a foreigner, according to newly introduced law, at the end of the 19th century. Biržai Castle – The construction of this earth bastion-type castle was ordered by Krzysztof Mikołaj "Perkūnas" Radziwiłł in 1586 and was completed in 1589. The castle became the main seat of the Biržai-Dubingiai line after it was moved from Dubingiai during the second half of the 17th century. During the Polish–Swedish wars in 1625, the castle was destroyed and surrendered. The family regained the castle in 1626 and rebuilt it from 1662 to 1669 in the Renaissance style. In the following war with Sweden in 1704, the castle and its fortifications were destroyed again and abandoned. At the beginning of the 19th century, the castle was sold to the Tyszkiewicz family. Radziwiłł Palace in Warsaw – Purchased from the Lubomirski family in 1674 by Michał Kazimierz Radziwiłł, the Nesvizh-Kletsk-Olyka line held the palace in its possession for 144 years until Dominik Hieronim died heirless in 1813. It was purchased in 1818 by the government of Congress Poland. It is the official seat of the President of the Republic of Poland. Nieborów Palace – Built between 1690 and 1696 on the site of an older castle, the palace came