 Soon after, the palace came to be called "Palais Martin" after Lubomirski's grandson.In 1720 the palace was rebuilt with the addition of a second, northern wing; and the interior was decorated with rococo paintings.After 1777 the palace passed into the possession of Poland's last king, Stanisław August Poniatowski, who hired the architect Domenico Merlini to redesign the rooms and to join the Royal Castle's library wing to it.