What is "sylvestrines"

The Sylvestrines are a congregation of monks of the Order of St. Benedict who form the Sylvestrine Congregation. The Sylvestrines use the post-nominal initials O.S.B. Silv. The congregation was founded in 1231 by Saint Sylvester Gozzolini. They are members of the Benedictine Confederation. Unlike most other congregations of the Order, they do not have any monasteries of nuns. The congregation is similar to others of eremetical origin, in that their houses are not raised to the status of an abbey, which would entangle the monasteries more strongly in the affairs of the world. The congregation, though, is led by an abbot general, the only abbot it has, who supervises all the houses of the congregation.