The "Hospital Chapel on the Martinsberg" is a flat-roofed sacred building with a semicircular choir and a bell turret.

The three-aisled rubble stone building dates back to the 12th century. Many details refer to the Romanesque period. The former side aisles and hospital buildings have not survived.

The choir area is illuminated by one rectangular window each in the north and south. The choir area, which is raised by 48 cm today through three steps, is separated from the rectangular church area by a triumphal arch. The church area is approximately 11.5 meters long and 7 meters wide and has three Romanesque clerestory windows each on the right and left, and two on the west wall.

A baroque renovation may have occurred around 1708, as there is a papal indulgence document from that year. In 1854, the chapel was left to decay; by 1890, only wall remnants remained. The little tower was only added during a roof renovation in 1898. The Holy Spirit Chapel is first mentioned in a letter of indulgence from 1332, issued in Avignon, now kept in the City Archive of Lahnstein. According to historical documents, a vicarage was already occupied before 1342. In 1505, a property near the Holy Spirit Chapel (not the hospital) was sold. The property near the Holy Spirit Chapel is also mentioned in 1575.

The chapel is situated by a freshwater spring, which was already said to have healing properties in the 14th century, and on the old high road from Oberlahnstein to the Erzbachtal (mining since Roman times), Bad Ems, and Nassau.

Christian von Stramberg reports on the legend of the wealthy Regina Waibelung, who founded a leper hospital due to heartbreak and cared for the sick there herself. When she fell ill herself, a spring emerged after a prayer, and she recovered after washing her hands. The healing spring was refurbished in 1972 with a natural granite basin and a commemorative plaque, and again in 2018.                                                                                                                                   The last interior renovation took place in 2000 by the “Association for the Preservation and Renovation of the Catholic Churches and Chapels of the Parish of St. Martin”. Nothing from the old furnishings of the chapel has been preserved.

Once there was a Stations of the Cross leading up to the Holy Spirit Chapel, which was observed during Holy Week and is now remembered by the street name “Auf’m Charweg”. Older citizens can still recall the Markus procession (April 25) and the petition processions on the three days before Ascension Day, which ended with a holy mass at the Holy Spirit Chapel.

Today, the former chapel is privately owned and cannot be visited.