The presence of an hourglass (or, to use the UK term, “sandglass”) in artwork from the late Middle Ages and Renaissance is often a symbol of the passage of time, and mortality; a sort of shorthand memento mori. The V&A's website describes their uses and manufacture:

Sandglasses were used in various situations: in churches, typically to time the sermon; on ships to time the length of the watches; in the kitchens of wealthy households, probably to help judge cooking times. They are often illustrated in scholars' studies where they served meditation, or simply helped judge the time of day.

Sandglasses in this period were constructed from two matching glass ampoules sealed (often with wax or pitch) and bound with fabric at the joint. The 'sand' was usually a material less sensitive to moisture such as powdered metal, rock or eggshell.

For more links on timekeeping, click here. See also Robert MacPherson's Pinterest page on hourglasses.

• Detail from the Allegory of the Good Government by Ambrogio Lorenzetti, c. 1338-1340
• School from the Coburg Pentateuch (British Library Additional 19776, fol. 72v), c. 1390-1396
• St. Jerome in his study, San Lorenzo, c. 1445
• A trompe l'oeil cabinet from the interior of the ducal palace at Urbino, from the workshop of Federico da Montefeltre, c. 1470-1480
• Detail from The Death of Mary from an altarpiece from Kärnten, c. 1445-1455
• Illuminated letter V from the Doctrinale of Alexander of Villedieu (ÖNB 2289, fol. 19v), c. 1465-1470
• Detail from the studiolo from the Ducal Palace in Gubbio, designed by Francesco di Giorgio Martini, c. 1478-1482
• Detail from St. Ambrosius, c. 1490-1500
• Detail from The Dream of St. Ursula by Vittore Carpaccio, 1495
• Detail from The Annunciation from the Mariapfarr altarpiece, c. 1495-1505
• A silver hourglass, 1506
• Knight, Death, and the Devil by Albrecht Dürer, c. 1513-1514
• Melencolia I by Albrecht Dürer, 1514
• St. Jerome in his Study by Albrecht Dürer, 1514
• Portrait of Sir Bryan Tuke by Hans Holbein the Younger
• Portrait of Johannes Zimmermann by Hans Holbein the Younger, 1520
• Portrait of a man by Moretto da Brescia, c. 1520-1525
• St. Jerome by Marinus van Reymerswael, c. 1521-1560
• Portrait of Lucas Hirscher, a judge from Kronstadt, by Gregorius von Bracov, 1535
• Portrait of Johann von Glauburg by Conrad Faber von Kreuznach, 1545
• A sandglass from the Mary Rose, 1545
• Portrait of Elisabeth von Königsegg by Hans Schöpfer the Younger, c. 1550
• Double-portrait of Martin Luther as a monk and as a professor by Jost Amman, second half of the 16th century
• Portrait of Georg von Roggenbach by Hans Sebald Lautensack, after 1554
• The Alchemist by Pieter Brueghel the Elder, 1558-1559 (also reversed, c. 1584?)
• Diptych of Peter Ulner by Bartholomew Bruyn the Younger, 1560
• Double portrait of Hans Furraht and Jacob von der Burch by Ludger Tom Ring the Younger, c. 1560
• The musicians in The Wedding at Cana by Paolo Veronese, 1563
• A grotesque in the commentary to the psalms of Orlando di Lassus and motets of Cyprian de Rore (Bayerische Staatsbibliothek, Cim.207), 1565
• Portrait of Herrmann Huddaus by Ludger Tom Ring the Younger, 1568
• Portrait of a man in the Portrait-Book of Hieronymus Beck von Leopoldsdorf, c. 1575-1585
• Death of St. Francis by Bartolomé Carducho, 1593
• Portrait of Margrave Georg Friedrich von Brandenburg-Ansbach by Heinrich Ulrich
• Four sandglasses in a single ebony frame, which probably each ran for different amounts of time, made in Italy in the late 16th century
• Sandglass in a turned ivory frame, made in Italy in the late 16th century