Thanks to the efforts of the Superior Abbot G. Engella (1718-1722), between 1719 and 1721 the Royal organ master J. J. Mosengel of Królewiec built church’s beautiful organs. The instrument, perfectly matched to the place, was initially designed as an eighteen-voice organ with two manuals, but during the works it was enlarged by a third manual and a pedal, a total of thirty-seven voices.
Like all instruments with a Baroque sound, the organ of Święta Lipka had mechanical tracker action, and the amount of air necessary for the instrument to play was pumped through four wedge-type bellows which were foot operated by the so-called organ blowers.
Jan Josue Mosengel attached great importance not only to the sound, but also to the decoration of the instrument. The extremely elaborate prospectus of the organ in Swieta Lipka, a work of the master’s workshop, is one of the most beautiful of the Baroque era.
The case is decorated with a gilded ornament of acanthus leaves. It was made by Christoph Peucker from Reszel. The finials feature sculptures of angels playing musical instruments. On the two highest towers stand the Virgin Mary and Archangel Gabriel – together with a dove, they form the Annunciation group. As they play, the statues, stars and bells on the towers are set in motion. Archangel Gabriel bows low, Mary responds with a nod, the angel on the central tower plays the lute and spins his head decorated with rays, and four little angels move the bells. Angels playing trumpets rotate on the posy.
Thanks to the richly carved setting of the main instrument and the music box built into the balustrade of the choir with movable figures, and the sound of the instrument, they were already counted among the best performed by J. J. Mosengel in those days. In 1721, convinced of their excellence, he wrote, when receipting the last payment from the sum due to him: „Gott erhalte das Werk bis an den Jüngsten Tag” (God save this work until the last day).