In a densely built-up urban space, such as the walled city of York, there is rarely an opportunity for archaeologists to investigate deeply buried archaeological remains. When this does occur, it is normally as a result of major redevelopments, such as the well-known excavations at York Minster in the 1960s, at Coppergate between 1976 and 1981, and at Hungate in 2006–2011. However, a lot of smaller archaeological interventions happen in between these ‘big digs’, and much of our knowledge of the development of the city comes from piecing together the evidence recovered as a result of regular monitoring of more modest projects, such as utilities replacement and upgrading.     

By the 18th century, York retained much of its medieval character, but the construction of more substantial brick buildings, followed by the arrival of large-scale industry and the railways during the 19th century, had a significant impact upon both the form and fabric of the city and upon the archaeological deposits beneath it. Luckily, there were local antiquarians who recorded as much as they could of the city’s Roman remains as they were unearthed by workmen. In the late 18th century, an apsidal Roman building was found while digging a new cellar for a house in Toft Green. A mosaic pavement was found nearby in 1814 and another apsidal building was discovered during the construction of the original railway station in 1840. This latter building featured a mosaic depicting a boscampus (a mythical beast with the body of a bull and tail of a fish). In 1853, a Roman townhouse containing more mosaics was found, the most complete of which featured the Four Seasons surrounding Medusa’s head.

These antiquarian discoveries show that the Toft Green area had been a wealthy suburb during the Roman period and held significant archaeological deposits. In view of this, NAA was commissioned in 2012 to carry out excavation and recording during repair works by Yorkshire Water, following the collapse of 80m of a Victorian sewer in Tanner Row and Toft Green.      

Except where cut by the trench for the Victorian sewer and some more modern disturbances, well-preserved Roman deposits were found at depths of between 1.2m and 4.1m below the modern road surface. Despite the narrow confines of the excavation, further restricted by the requirement for extensive shoring of the deep trench, significant remains of a high-status Roman building were identified. The area for this structure had been levelled-up with a dump of clay that overlay the natural ground surface. One of the rooms contained a tessellated floor, part of which was lifted and conserved, and the building also had plastered and painted walls. The location of these remains, together with the character of the recovered sections of mosaic, suggests that the rooms may have formed part of a larger structure connected with the apsidal building containing the boscampus mosaic found in 1840, although whether this was a large townhouse or a complex, such as a temple or bath-house, remains to be resolved. The building was probably constructed in the mid-2nd century and modified over time, with successive floor surfaces and reapplied wall plaster. The pottery assemblage associated with the building supports its high status, with a high proportion of amphorae, fine-wares, such as samian, and table-wares, including flagons and bowls. Several items, such as a tazze, a candlestick, an unguent pot and a face-pot, may suggest ritual activity. An area of stratified soil layers and surfaces to the south-west probably represented an external garden or yard area.  

Several walls that ran on varying alignments represented either change to the layout or later buildings. However, by the mid-3rd century, a period of abandonment and collapse of the building was represented by layers of rubble and dumping. The area was subsequently reused, with a new sequence of floors laid over the rubble. These were cut by a pit containing 4th-century material. Finds elsewhere along the trench included dumps of painted plaster rubble, which may relate to the building containing the ‘Four Seasons’ mosaic discovered in 1853.

The work undertaken at Toft Green demonstrated NAA’s capability to investigate, understand and record complex and significant archaeological remains within the constraints of a severely restricted working environment and against a tight deadline. Working in close collaboration with the other contractors, this enabled the client to complete the sewer reconstruction while successfully mitigating the impact upon York’s Roman heritage.