What is "olyftack"

The Olyftack (Olive Branch), or in full Gulde van den Heyligen Geest die men noempt den Olyftack (Confraternity of the Holy Spirit called the Olive Branch) was a chamber of rhetoric that dates back to the early 16th century in Antwerp, when it was a social drama society drawing its membership primarily from merchants and tradesmen. In 1660 it merged with its former rival the Violieren (which was more closely associated with artists and intellectuals), and in 1762 the society was dissolved altogether.