The article deals with Spanish set expressions that include a foreign proper name. The study overviews phraseological units, as well as proverbs and sayings included in the most important Spanish lexicographical works. Dealing with an onomastic (onymic) component requires the description of idioms, their origin, meaning and the degree of linguistic actuality. The study of the selected number of set expressions and proverbs has revealed that some proper names may be considered as international precedent onyms (anthroponyms, mythonyms, poetonyms, etc.) This type of proper names may be interpreted as part of the world cultural legacy, since they are present in the onomastic fund of many languages and are considered a sort of linguistic constant formed throughout human history. Spanish national and cultural identity may be illustrated by idioms with a foreign toponym or anthroponym. Generally, those are set expressions and idioms that allude to some historical events and reflect Spanish military and political activities in the world arena, Spanish cultural and linguistic contacts in different periods. The study of idiomatic phrases, their origin and motivation has revealed the key sources to replenish the Spanish phraseological fund, which are world literature, cinema, classical mythology, the Bible, military and political activities. Chronologically, the majority of the analyzed idioms was created in the Middle Ages and the Modern period, however, foreign proper names continue to replenish the Spanish lexis, since there are many expressions and proverbs with a foreign onym that have been created in the recent centuries.