The Gaelic word ‘port’ nowadays means simply ‘a tune’, but in the 17th century it seems to have referred to a specific kind of instrumental music for the Gaelic harp.
...that species of music which is now scarcely known, I mean, the Port. Almost every great
family had a Port that went by the name of that family. Of the few that are still preserved
are, Port Lennox, Port Gordon, Port Seton, and Port Athole. which are all of them excellent
in their kind. The Port is not of the martial strain of the march, as some have conjectured;
those above named being all in the plaintive strain, and modulated for the harp.
These ports can be characterised as being in two parts. The first part is more unmeasured, rising from very low on the instrument’s range, and then sinking back down at the end. The second half is more measured, in either 3 or 4 time, and typically ends rather indifferently.
Below is a video of a live performance of ‘Port Preist’ from the Straloch lute book, 1627-9, played by Simon Chadwick on a replica of the 15th century ‘Queen Mary’ harp.
Later sources from the 18th century, such as Bowie5 include more ports, including three of the four named by Tytler above. A number of the ports are attributed to Rory Dall6.
Tytler’s comments suggest that the popularity of the ports waned during the 18th century to the point where scholars were not too sure of their significance. We are lucky that so many were notated.