On a proper construction of Article 5(1) of the Convention of 27 September 1968 on Jurisdiction and the Enforcement of Judgments in Civil and Commercial Matters, as amended by the Convention of 9 October 1978 on the Accession of the Kingdom of Denmark, Ireland and the United Kingdom of Great Britain and Northern Ireland, by the Convention of 25 October 1982 on the Accession of the Hellenic Republic, and by the Convention of 26 May 1989 on the Accession of the Kingdom of Spain and the Portuguese Republic, the place of performance of the obligation, within the meaning of that provision, is to be determined in accordance with the law governing the obligation in question according to the conflict rules of the court seised.