What is the burden of proving a foreign marriage?

In short, a person attempting to rely on a foreign marriage has the burden of proving its validity by establishing the essential requisites of a valid marriage according to the law of the foreign country. Whether there is sufficient evidence in a particular case is a question of fact requiring proof on a balance of probabilities. Information as to the law of the foreign country must be provided by someone conversant with the law of that jurisdiction; generally the courts have required expert evidence. On that point, I refer to the summary in Halsbury’s Laws of Canada, Ascertaining Foreign Law (2011 Reissue), at paragraph HCF-98: … It is not necessary that the expert be authorized to act as a legal practitioner in the place of the law in question, but he or she should be a person whose occupation makes it necessary to have knowledge of the relevant law. The competence and qualification of the expert witness is a matter for the assessment of the court. [Gold v. Reinblatt, 1928 CanLII 87 (SCC), [1929] S.C.R. 74.] I would add here that, in this electronic age, where appropriate, it is possible that reliance may be placed on information obtained from a reliable electronic source where it is provided to the court by means of an explanatory affidavit.