Double-decker is a contemporary and colloquial name for a type of fiddle/violin with sympathetic strings where the pegs are ordered in two rows in the peg box. The pegs for the playing strings are placed in the upper rows and those for the sympathetic strings in a row below or behind the other pegs. There is no official name of the fiddle type and nobody knows what they were called when they were built. Violino d'amore is a possible name but not specific enough to distinguish these fiddles from other violins with sympathetic strings. In his essay contribution to the knowledge about viola d'amore" Daniel Fryklund wrote the following about the swedish double-deckers: In Sweden I have found several specimens of a peculiar type of violino d'amore with 4 playing strings and 8 sympathetic strings. The later are mounted in small pegs, placed behind the larger pegs for the playing strings in a pegbox which has been expanded backwards. I haven't heard of such a placement of the pegs on any other instrument. Fryklund also writes that since both the signed instruments that he has seen of this type are built in Sweden (Scania/Skåne), the instrument model might be specific for Sweden. He also suggest that these fiddles have been common but later converted to standard violins. In the recent decades many more double-deckers have been discovered and Fryklund hypothesis is more or less confirmed even though some signed instruments have been built in other parts of southeastern Sweden. In total, 23 double-deckers have been discovered in Sweden, in museums, owned by private individuals and a few pictures of instruments that unfortunately has disappeared. The best outcome of an analysis of these double-deckers is an hypothesis that the instrument type originated among professional luthiers in northwestern Scania during the first half of the 18th century. The first signed specimens are built by Arwit Rönnegren and Johan Georg Mothe, who both came to Sweden in 1722 after being prisoners of war in Russia for 13 years following the battle of Poltava and the surrender at Perevolotjna during the Great Northern War. When Mothe applies for citizenship in Ängelholm in 1723 he claims that he learned violin making during his time as prisoner of war and that he wanted to settle in the city and practise as a luthier. It is not known who taught Mothe violin making. It could be Rönnegren but it is more likely that it was another prisoner that might not have returned to or moved to Sweden after being released following the Treaty of Nystad in 1721. The instruments made by Rönnegren and Mothe seems inspired by the style of Joachim Tielke in Hamburg or some other luthier in northern Germany where there was a habit of building violins with lion heads instead of a scroll which is also the case for most double-deckers. There are also a few viola d'amore built by Johan Christian Hoffman in Leipzig that has the sympathetic strings attached near the end pin in the same way as the double-deckers and this could further point to an inspiration from northern Germany. However, as there are no preserved instruments from Germany with a two-level pegbox, it is both possible that Rönnegren or Mothe came up with this idea but was inspired to the style of decorations or that they also got the idea to the two-level pegbox from a german tutor but that all such preceding instruments from other countries have been lost.
Rönnegren and Mothe was the first representatives of a cluster of luthiers in northwestern Scania and Mothe was followed by his son and granson and several apprentices in their workshop and there are preserved double-deckers built by one of these apprentices. From Ängelholm the ideas was later spread to other professional luthiers in Stockholm and possibly other larger cities, and to less professional luthiers among common people in the country-side and smaller towns but there are very few signed instruments with origin outside the Ängelholm cluster.
Except of a strange hardanger fiddle and a newer viola d'amore trend in India there are no known violin-like instruments where the pegs are placed in two rows in the pegbox. The only preserved instrument which might indicate a foreign origin of the Swedish double-deckers is the peculiar tenor violin M132. Of the 23 double-deckers that are found in Sweden, 8 of them are signed and an additional 4 can be traced to the signed instrumentens due to similarity. It is not possible to claim that the unsigned instruments are built in Sweden but they are found here and there are no evidence that they are built elsewhere. The hypothesis that double-deckers are endemic to Sweden is currently not possible to falsify. As earlier mentioned, the oldest signed double-deckers built in Scania during the first half of the 18th century and in total 9 of 23double-deckers instruments are from Scania.
It is worth mentioning that the double-decker and the norwegian hardanger fiddle seems to have completely different origin, which is the opposite to what most people would guess. Also there are no double-deckers found in Denmark event thought it is very close to Scania. Probably the relations between Sweden and Denmark were not great in the 18th century after the danish declarations of war in 1700 and 1710.
Double-deckers have the following features (to different extent).
There is no known music written for the double-deckers or any documentation of which music that double-deckers were used for. It would have been interesting to know who the customers to the luthiers in Ängelholm were. I guess it was more or less professional musicians or hobby musicians in the higher classes. The distinction between different genres (classical or folk music) was not as obvious as today and some professional musicians such as bell-ringers also had a role in providing entertainment music for the peasantry. The double-deckers seems to have later been spread to less professional luthiers and my guess is that they also became more common among local folk musicians. When sympathetic strings went out of fashion the price of double-deckers have probably decreased and they might have been sold to fiddlers in the country-side. There are tales from late 19th century and early 20th century about local fiddlers playing on instruments with sympathetic strings and scordatura (retuning) is common in Swedish folk music. The anthropologist Carl Erik Södling found a double decker in Slaka, Linköping in late 19th century and claimed it was common among fiddlers in the countryside and that is at least some kind of evidence of usage in swedish traditional music. We do not know how the double-deckers were tuned but scordatura is common for hardanger fiddles and viola d'amore and is very probable for double-deckers as well. My experience of double-deckers with 8 sympathetic strings is that they are less of a drone instrument than fiddles with fewer sympathetic strings. Many sympathetic strings acts as a general reverb and reacts to more than just the most important tones in the scale. There is also possibility that the sympathetic strings on double-deckers with 8 under strings were tuned in four pairs to strengthen the drone effect. As long as we don't know we are all free to choose how to use the double-deckers and what music to play.
The diagram above is based on place of construction.