Daphni Monastery is built on an exceptional site at the western entrance to the Attica Basin, on the edge of the forest at Chaidari. It is situated approximately halfway along the Sacred Way leading from Athens to Eleusis, probably on the site of the sanctuary of Apollo Daphnaios. The monastery is protected by a strong, square defensive wall with battlements, square towers and two gates. The surrounding wall encloses the catholicon , which is dedicated to the Dormition of the Virgin Mary, as well as the remains of the cells and the other buildings, such as the kitchens and refectory.

As a large and wealthy institution, the monastery may owe its foundation to circles in the imperial court. That being said, the donator’s identity and the precise foundation date remain unknown, since no inscription or other evidence yielding definitive information has yet been found. The catholicon or principal monastery church dates to the second half of the 11^th century, and is of the octagonal type found in mainland Greece, without galleries , but with a narthex and more recent two-storey portico to the west. Sixteen single-lobed windows in the drum of the dome cast light evenly into the church interior. Thanks to the absence of galleries, from the outside the building appears to rise like a pyramid to the top of the dome. The walls were built of cloisonné masonry ; large white blocks of stone were used from the ground up to window level, laid in a cross formation typical of the mid-Byzantine tradition in Greece proper.  The ceramoplastic decoration is limited to a band of meanders in the upper section of the sanctuary apse, dogtooth bands around the window arches and above the cornice, and limited use of kufic ornaments .

An open portico added to the western part of the church in the early 12^th century was later built up and converted into an exonarthex . Its appearance was altered by Cistercian monks, to whom Otto de la Roche, Duke of Athens, granted the monastery in 1207. Lancet windows typical of western architecture have thus survived in the facade, probably in place of what were originally Byzantine arches. At the same time, the crypt below the narthex was converted into a mausoleum for the dukes of Athens, and a western-type monastery cloister consisting of a square courtyard with galleries was built to the south. When Athens was taken by the Ottoman Turks in 1458 the monastery was returned to Orthodox monks. In Late Byzantine times a peculiar north-oriented chapel was constructed to the west of the exonarthex.
 
In 1840, following the Greek revolution, the monastery lost its community and was abandoned, only to be pressed into service as a public lunatic asylum. In the late 19^th century continuous earthquakes put the catholicon at risk of collapse. Repair work followed, during which the dome was replaced and the mosaics repaired by Italian restorers. Some depictions were moved from their original position during relaying, while others were added to. The interior of the catholicon was laid out in the manner well known in the renowned buildings of Constantinople, with (now lost) marble revetments and sculpture decoration in the lower section of the church, and mosaics in the upper section.

The exceptional set of mosaics follows the iconographic programme established after the end of the iconoclast controversy , reflecting new dogmatic beliefs centred on the Incarnation of the Lord. The austere figure of the Pantocrator rendered in metal thus dominates the dome, surrounded by prophets in the drum. The sanctuary niche has a depiction of the Virgin Mary enthroned, accompanied by archangels. Scenes from the Christological cycle are rendered on the squinches , the arches and the surfaces of the cross arms, together with saints and prelates at other points in the church. The iconographic programme is rounded off in the narthex with scenes from the Passion Cycle and the life of Virgin Mary. All the figures are represented in the right proportions, displaying restrained movement, while the harmony and symmetry of the compositions point to art strongly rooted in the classic tradition. Typical of this is the posture adopted by the prophets in the drum of the dome , which is reminiscent of ancient philosophers, as well as the graceful female figures in the narthex compositions. The Crucifixion scene in the church’s northern cross-arm renders the grief on the faces of the Virgin Mary and John in a unique manner. The flawless workmanship displayed in the church decoration point to a founder of considerable means, and artists trained in a Constantinople workshop.

These exquisite mosaics date to somewhere between the 10^th and late 11^th century rank; in terms of quality they rank among the masterpieces of Byzantine art. Their classicistic character has recently led them to being assigned to the reign of Constantine VII Porphyrogenitus (913-959), though the general consensus is that they date to the late 11^th century.

The monument has been on the UNESCO World Heritage List (WHL) since 1990.