This article addresses domicile from a UK viewpoint, although other systems derived from UK common law have similar basic rules.
Domicile is at first sight an elusive concept. The UK version could be said to have been designed to preserve the jurisprudential singularity, if not insularity, of the British. At times it seems illogical, with results which sometimes conflict with common sense, until one understands the logic of its principles. Hard law makes good law.
The fundamental principles were laid down by (principally) the English Courts through the 19th century, and through the 20th century have stood the test of scrutiny, increasingly within the sphere of taxation, so that, standing on the brink of the 21st century, we can speak confidently about them. Indeed, a lawyer from the late Victorian age would feel as comfortable as we do. This is important, when so much financially may depend on applying correctly the laws of domicile.