Sicco van Goslinga was a 'grietman' of Franekeradeel, a kind of mayor. He lived from 1664 - 1731. He was a member of the States of Friesland and also of the States General of the Republic of the Seven United Netherlands. As a diplomat he played a big role in the Peace of Utrecht. He had 3 daughters. In order to remember the family name this mausoleum was made. The restoration was far from easy. Algera made his own paint. Van Goslinga had many connections with important Frisian aristocratic families, such as Van Aylva Scheltema, Cammingha and others. Their names are mentioned on the mausoleum.
In the radio-link on this site is more information about the special restoration.
More about the earlier restoration of the church: https://www.omropfryslan.nl/nieuws/311310-eerbetoon-sicco-van-goslinga