Rüti Abbey
In the late Middle Ages, Einsiedeln sold the island to the Counts of Rapperswil who used its sandstone besides the Bollingen quarries to build the town of Rapperswil. On 12 May 1433 "Heini Murer von Grueningen" and his wife "Anna Keller" confirmed the transfer of their lands on "Lutzelnoew" for "100 Pfund Pfennig Zürcher Währung" to the Abbot "Johans" and the convent of the Rüti Abbey, including buildings and lands in the Herrschaft Grüningen, and to be enrolled in the abbey's "libri anniversariorum" (German: "Jahrzeitbuch").