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The Encyclopedia of Horology

Clock · Mirror clock

Mirror clock

Partially verified

This mirror clock, or Spiegeluhr, originates from late-Renaissance Nürnberg, Germany. The object features a gilded brass and copper case supported by an elaborately decorated stem and openwork foot. Its design incorporates grotesque ornament, such as hybrid human and animal figures, satyrs, and masks in high relief. The dial integrates a complex astrolabe with a revolving rete and a reversible tympan, alongside a revolving calendar ring indicating months, days, and Saints’ Days. The movement, housed in a plated iron frame with iron wheels, was originally equipped with striking trains for hours and quarters, though many of these components are now missing. Currently, the clock acts as a simple timepiece, modified with a short pendulum and lacking several original mechanisms, including the moon hand and bells. It is attributed to the maker with the initials “C.R.”

Front view of the mirror clock showing the dial with the astrolabe rete and calendar ring.
Front view of the mirror clock showing the dial with the astrolabe rete and calendar ring. — The Metropolitan Museum of Art. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.metmuseum.org
Category
Clock · Mirror clock
Maker / attribution
Master CR
Reference
Not recorded
Catalogue / lot identifier
17.190.639
Source-reported date
ca. 1565–70
Source-reported place
Germany

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case and Dial Design

The clock is configured as a mirror clock, a form historically referred to as a monstrance clock. The structure rests on an openwork foot and is supported by a hollow stem featuring grotesque ornamentation. These decorations consist of satyrs, masks, and hybrid creatures rendered in high relief. The design elements on the base are compared to drinking vessel designs from 1551.

The dial includes a central astrolabe with a rete and a reversible tympan calibrated for 40 and 50 degrees latitude. A concentric revolving calendar ring tracks the months, days, and liturgical information. The outer chapter ring provides hour indication (I–XII) and incorporates touch pins intended for operation in low-light conditions.

Evidence for this section
  • “The hollow stem of the case is covered with a distinctive variety of ornament called grotesque”
  • “The tympan for the Museum’s clock is reversible and can be used for 40 degrees latitude on one side and 50 degrees latitude on the other”
  • “The numerals on the hour chapter are augmented by touch pins for using the clock in darkness.”

Movement and Mechanical Features

The movement is constructed with two circular iron plates held by four cylindrical pillars. It originally featured a going train and two striking trains with iron wheels, designed for twelve- and twenty-four-hour intervals. The system employed open springs and retained remnants of stackfreed regulation.

The clock has undergone significant modifications. An anchor-shaped weight with a short pendulum replaced the original balance. The motion work for the astrolabe and calendar, along with the bells for striking, are no longer present. The solar and lunar hands, as well as pointers for the calendar, are partially or entirely missing.

Evidence for this section
  • “The movement consists of two circular iron plates that are held apart by four cylindrical iron pillars.”
  • “A short pendulum with an anchor-shaped weight has been substituted for the original balance.”
  • “all of the underdial motion work for the astrolabe and the calendar is now missing, as are the bells for both the hour- and quarter-striking mechanisms.”

Attribution and History

The clock is attributed to the Nürnberg workshop of Master CR, a maker identified through initials on a series of similar timepieces.

The object represents a specific style of metalwork produced in Nürnberg during the second half of the sixteenth century. It entered the Metropolitan Museum of Art as part of the J. Pierpont Morgan collection. Before this acquisition, the provenance of the clock remains undocumented.

Evidence for this section
  • “Most of these clocks are signed by an as-yet-unidentified clockmaker with the initials “C.R.””
  • “The Museum’s clock is not signed, which is probably due to the fact that the cover for the back of the movement is a replacement of the original.”
  • “Nothing is known of the clock’s provenance before J. Pierpont Morgan acquired it.”

Open research questions

  • What is the specific composition of the missing bells' striking mechanism in relation to the upper drum unit?
  • Can the iron wheel configuration be fully mapped to confirm the exact nature of the original striking trains?

Source evidence

Recorded claims and source quotations for Mirror clock
FieldSource-reported valueSource quotation
MakerMaster CR“Most of these clocks are signed by an as-yet-unidentified clockmaker with the initials “C.R.””
MediumGilded brass, gilded copper, iron“Case: gilded brass and gilded copper; Dial: gilded brass; Movement: plated frame of iron, iron wheels”
Accession number17.190.639“17.190.639”
Dateca. 1565–70“ca. 1565–70”
FunctionMirror clock“they were called mirror clocks (Spiegeluhren)”
Original strikingTwelve- and twenty-four-hour“The movement contains a going train and two striking trains of iron wheels, originally laid out for twelve- and twenty-four-hour striking.”
ProvenanceGift of J. Pierpont Morgan“Gift of J. Pierpont Morgan, 1917”

Visible details

  • Grotesque relief ornament on stem and base
  • Astrolabe dial with central rete
  • Revolving calendar ring around the dial
  • Touch pins on the hour chapter numerals

Research qualifications

  • The clock movement appears to have been modified; the original balance was replaced by a short pendulum with an anchor weight.
  • The back cover of the movement is not original, which may account for the absence of a maker's mark.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Mirror clock

Reviewed 2026-10-26 · Record 4614663edd

Terms in this record

Glossary explanations for terms named in this object’s record.