Cezary Augustyn Plater (5 September 1810 – 9 February 1869) was a participant in the November Uprising and Polish émigré activist.

[1] He returned to Lithuania and participated in a partisan campaign in the Ukmergė district, alongside his cousin Emilia Plater.

On December 19, 1834, he signed the founding act of the United Brothers Masonic lodge and contributed to the establishment of Bohdan Jański [pl]'s house.

In December 1838, he arrived in Rome as an agent of Prince Adam Jerzy Czartoryski and met with Pope Gregory XVI.

The poet repaid Plater with a poetic letter entitled Jeślim ci kiedy był przykro przeciwny...

He founded and managed several charitable institutions, including the St. Vincent de Paul Society, an orphanage, an elderly care home, a hospital, a savings and loan fund, and a farming circle.

The daughters, Maria and Jadwiga Stefania, married into prominent princely families, respectively to Stanisław Światopełk-Czetwertyński and Karol Wilhelm Radziwiłł.

Ludwik Kazimierz settled in the Niekłań Wielki estate, which he transformed into a major center of the mining and metallurgical industry.