Gotthard Kettler was born in Westphalia; at the age of twenty he joined the Order of Livonia and in 1559 was elected Master of the Order. After its dissolution he became the vassal of the king of Poland-Lithuania and the governor of the newly established Duchy of Courland-Semigallia. Kettler consolidated the power of the Lutheran church in the Duchy. During his time (1562-1587) seventy churches were built as well as eight schools and eight asylums for the poor were established in Courland.
According to his last will, he was buried without excessive luxury – in a white gown, in a commonly shaped pewter sarcophagus with fine engravings and the coats of arms of Mecklenburg and Courland. The sarcophagus was presumably made by a pewterer from Riga, Cyriak Klinth. The restoration of the sarcophagus was completed and the burial was consecrated in 2011.