31 January, 2014

Squirrel-proof bird feeders – or maybe not

Grey squirrels have become very successful in most of Britain since they were introduced from North America in the nineteenth century.  Agile and ingenious, the local squirrels rarely take long to spot that a bird feeding station is a handy source of free food.  Or, for that matter, to figure out how to defeat, circumvent or otherwise overcome attempts to keep them away from the food.  Here’s one grey squirrel at a wildlife site that has figured out how to outwit the (supposedly) squirrel-proof feeders:

The white plastic skirt and cage around the trunk of the tree holding the feeders is a baffle, designed to stop squirrels climbing up from the ground.  It may well be very effective at that – but this squirrel ran up a nearby tree, leaped across the gap, and ran down the tree holding the feeders

While hanging on to the tree with its back legs, the squirrel can stretch across to the feeder...

...and tuck in

Even when the feeder is too far from the tree to stretch across from the trunk, the squirrel is not deterred.  Just run back up the pole, out along the branch, and swarm down to hang on to the feeder itself.

Bird feeder designers: Nil.  Squirrel: 1.  Which is the usual scoreline.

18 January, 2014

The Crosby Garrett Helmet

The Crosby Garrett Helmet is a spectacular example of a Roman cavalry sports helmet, in the form of the face of a young clean-shaven man with luxuriant curly hair, wearing a Phrygian cap (shaped like a bent cone) topped by a winged griffin.
The Crosby Garrett Helmet on display. Photo by Daniel Pett, available under Creative Commons on Flickr

For more photographs, see the Portable Antiquities Scheme record.

The helmet is constructed of copper alloy.  The visor shows traces of having been tinned, so the face would originally have been a silvery colour.  The helmet was well-used, with signs of wear from the visor being opened and closed, and had been repaired with a sheet of bronze riveted over a split. The bowl of the helmet was broken into many pieces when discovered, and had been folded before being buried. The face mask was intact and had been placed face down. For more details, see the Portable Antiquities Scheme record and the initial report by Ralph Jackson.

The helmet was discovered by metal detectorists in 2010, buried in pastureland near the hamlet of Crosby Garrett in the Eden Valley, northern England.

Map link: Crosby Garrett

An archaeological investigation of the find spot was conducted by Tullie House Museum (Carlisle) and the Portable Antiquities Scheme. This has now been published (Breeze and Bishop [Eds] 2013), and is also reported in the February 2014 issue of Current Archaeology (CA), Issue 287.

The field where the helmet was found is on sloping ground on a ridge plateau.  Survey identified the remains of earthworks surrounding a large ditched enclosure measuring 500 metres along its southern edge (other dimensions and full size unknown). The shape of the enclosure is consistent with a local settlement, rather than a Roman fortification. However, there was a short straight length of earthwork outside and parallel with the enclosure boundary, resembling the defensive structure called a titulus that protected the entrance to Roman temporary military camps, perhaps indicating that the inhabitants had chosen to copy a Roman military construction technique.

Within the enclosure more low earthworks surrounded a much smaller enclosure shaped ‘like a fattened kidney bean’ (roughly 100 m on its long axis by roughly 60 m on its short axis) and a hut circle.  Geophysical survey identified more hut circles, a rectangular building and a variety of terraces and boundaries, with the buildings tending to concentrate in the northern half of the area surveyed.  Stuart Noon, the Finds Liaison Officer interviewed for the CA article, suggested that the lower area of the settlement could have been used for outbuildings and perhaps a paddock.

The helmet find spot was on a terrace where buildings had stood during the Roman period, directly in front of a boundary ditch, and at the lower end of the settlement in a place that has ‘an amazing view’.  Excavation of a small trench on the spot indicated that the helmet had been buried in some form of artificial stone construction, with two layers of stone cobbles set in soil on top of two paving slabs.  The helmet had been placed on the slabs, soil mounded around it, and the stone cobbles put on top as a cap. There was no wear on the cobbles, suggesting that they were not a road or track surface.  Stuart Noon described the structure as cairn-like, and suggested that it was a formal monument.  He also suggested that the weight of soil may not have been enough to crush the helmet bowl, as the helmet was buried only 50 cm deep, and thus that the helmet may have been deliberately broken before it was buried, suggesting a ‘ritual connotation’. 

Two Roman coins were found in the trench. One was a coin of Constantine from 300–335 and the other, in a cavity in the cobbles, was a barely worn coin of Constantius II dating to 335–337.  There were also some fragments of copper alloy that could be more fragments of the helmet, a blue glass bead, and an unidentified iron object that might possibly be part of a weapon. These may indicate that the helmet was buried with other objects, and the coins may date the construction of the cairn-like structure.  The decorated rivets that would have held the strap to fasten the helmet are of a type dated to the late second to third century AD.  So, if the two fourth-century coins date the burial, the helmet would already have been old when it was buried.  (Caveat: the coins can indicate the earliest possible date at which they were buried, since they cannot have been buried before they were made, but not the actual date, since they may have been buried many years after they were made.  The unworn coin had presumably not been rattling around someone’s pocket or being handed around in numerous transactions, otherwise it would show signs of wear, but it could have been sitting undisturbed in a protected environment such as a strong box.  So the helmet is considerably older than the coins, but both might have been old when they were buried).

Helmets of this type were used for a military display-come-training-exercise called the hippika gymnasia, in which elite cavalry units staged a mock battle watched by important dignitaries, sometimes the Emperor himself.  Mike Bishop explains in the CA article that cavalry sports helmets first appeared in the first century, initially as face masks that could be fitted to ordinary cavalry helmets, became progressively more ornate through the second and third centuries, and disappeared by the fourth century after Emperor Diocletian (285–304 AD) reformed the army. During the late second and third century, it was fashionable to stage the hippika gymnasia as a sort of re-enactment of the Trojan War legends. The Phrygian cap was a style associated with the east and could be used to signify a Trojan.

Unlike combat equipment, which was Roman Army property and had to be returned at the end of service, sports helmets were the personal property of individual cavalrymen and can be found in non-military contexts (Jackson 2010).

Among the many interesting issues raised by the article, two particularly struck me.

The first was the idea that the helmet may have been old when it was buried (if the coins date the burial, maybe a hundred years old or more).  This suggests that it may have had several owners, one of whom chose to bury it.  It’s not surprising that the helmet might have had several owners; it looks an expensive and prestigious item, and unless it was badly damaged in a mock battle it could probably be expected to last longer than one term of service.  Perhaps some soldiers sold their sports equipment on to colleagues when they left the army, if they reckoned that the cash would be more useful to them in setting up their retirement, or perhaps gave items as gifts to close comrades or protégés.  Or perhaps the personal possessions of soldiers who died in service were auctioned off to their colleagues and the money sent to their families, rather than trying to ship personal effects home.  Or, for that matter, maybe some managed to lose their equipment to a colleague in a bet or a duel.  Either way, maybe the helmet had a long and varied life being handed on to successive soldiers in an elite unit before one of them decided to take it home when he retired.  Another possibility is that it could have been a family heirloom inherited by successive generations of a family living at Crosby Garrett, either as a piece of equipment actively used by successive owners (e.g. if the family had a tradition of sons following their fathers into the cavalry), or as an ornamental heirloom displayed on the Roman equivalent of the mantelpiece to commemorate an increasingly distant ancestor.

If the helmet had several owners, why might one of them have chosen to treat it differently, by burying it in a cairn rather than passing it on?  This is a question to which we can never know the answer. One possibility is that the last owner brought it home and interred it as a symbolic way of marking his discharge from the army. Another is that it was interred as a memorial to someone with whom it was especially closely associated.  Or perhaps the last owner had no-one to pass it on to – if it was a family heirloom, perhaps there was no son or son-in-law or grandson to inherit, or none who had a need or desire for a sports cavalry helmet – and so it was buried by the family when the last owner died. 

If the coins date the burial to the 330s or later, I wonder if a couple of specific cultural changes could have played a part. If Diocletian’s army reforms abolished the hippika gymnasia this may have rendered the helmet obsolete. In which case, even if there was a son who had followed his forebears into the traditional cavalry unit there may have been no use for the helmet, and a dignified burial as a memorial to the last family member to perform in a hippika gymnasia may have seemed appropriate.  Religious change could be another possibility.  The Emperor Constantine showed overt favouritism to Christianity after he won the Battle of the Milvian Bridge in 312, and Christianity became the official state religion in 381.  The pagan god Mithras is always depicted wearing a Phrygian cap, very similar to the Crosby Garrett helmet.  The Mithras mystery cult was very popular in the Roman army, and would surely have been well known to anyone serving in a cavalry unit.  Even if the Crosby Garrett helmet originally signified a Trojan, it may also have come to be associated with Mithras.  As Christianity became the prevailing religion in the Roman Empire during the fourth century, owning a helmet that looked like a pagan idol may have become a bit embarrassing, perhaps even dangerous if it attracted hostile attention from zealous Christians. In which case, respectfully interring it may have seemed appropriate, possibly to mark a conversion to Christianity.

It is interesting that the helmet was buried on a terrace with an impressive view over the landscape.  Perhaps that just happened to be the owner’s favourite spot, where he liked to stand and survey his domain (or just admire the view) and so it was a suitable place for a memorial.  However, it does remind me of the location of some Bronze Age tumuli, such as the one on nearby Wild Boar Fell which is placed not on the broad flat summit of the fell (where it would be invisible except to someone right on the summit plateau), but at the break of slope on the edge of the summit ridge, where it commands a wide view and is visible on the skyline to someone looking up from the valley below. There is a theory that some of these tumuli were positioned as a claim of ownership over the lands that could be seen from them, and I wonder if the burial spot for the Crosby Garrett helmet could have been chosen for the same sort of reason.   

Map link: Wild Boar Fell

As well as the helmet’s age, the second issue that caught my attention is the presence of what appears to be a substantial, previously unknown, Roman-period settlement in the upper Eden Valley, presumably with considerable wealth as the Crosby Garrett helmet must have been an expensive and prestigious item.  The hut circles suggest that traditional building forms were in use, yet the titulus may indicate familiarity with Roman military techniques and a willingness to adopt those that were considered useful.  The presence of the Crosby Garrett helmet indicates some sort of connection with an elite Roman cavalry unit.  The connection could be merely one of loot, or possibly a one-off trade transaction, if someone happened to see the helmet, liked the look of it and bought it. Or it may indicate some more substantial relationship. Cavalry auxiliaries in the Roman army were routinely recruited from the provinces.  Perhaps someone from the Crosby Garrett settlement served as a Roman cavalry auxiliary and brought his prestige sports helmet home when his service was finished, or perhaps a cavalryman serving at one of the Roman forts in the area married a local girl and settled down with her.  There may also be a possibility that the settlement supplied the Roman army with something.  It’s not difficult to imagine a retired cavalryman taking up horse-breeding and horse-training, and supplying cavalry mounts to his former colleagues as a profitable business.  As the helmet is second- or third-century and the Roman coins are fourth-century, it may indicate a long-term connection between the Crosby Garrett settlement and the Romans, perhaps extending over several generations.  Again, it is not hard to imagine a family developing a tradition of sons and grandsons serving in their fathers’ and grandfathers’ old cavalry unit, and/or supplying horses to it, although this is pure speculation.

Speculating further, one of the models for the transition from Roman administration to small post-Roman kingdoms postulates that some Roman fort commanders may have become local warlords as central authority broke down, supporting themselves by collecting supplies from the local population instead of taxes when the salary payments stopped arriving.  Such a process would have been smoother – indeed, may have been effectively underway long before the formal end of Roman rule – if local Roman commanders were already closely integrated with the local tribal leaders.  If the finds at Crosby Garrett do indicate an important local settlement with strong ties to the Roman army, it would fit easily into this sort of model.  It may even be significant that Crosby Garrett is in the Eden Valley, which is one of the (many) candidates for the location of the sixth-century kingdom of Rheged (see earlier posts on the location of Rheged here and here). I need hardly say that this is so tenuous that it doesn’t even qualify as speculation.  Nevertheless, the idea that the heroes of sixth-century Rheged might have had some distant connection with the Roman elite cavalryman who owned the spectacular Crosby Garrett helmet has a certain romantic appeal.

Breeze DJ, Bishop MC (Eds). The Crosby Garrett Helmet. The Armatura Press, ISBN 978-0-9570261-7-9 (£5). Excerpt available online.
Jackson R. Roman Cavalry Sports helmet from Crosby Garrett, Cumbria. Report for the Portable Antiquities Scheme, 2010. Available online