I want to combine 2 sentences with a relative pronoun.
Example:
Ich habe einen Hund. Mein Hund hat den Briefträger gebissen.
Result:
Ich habe einen Hund, der den Briefträger gebissen hat.
So "den" is the relative pronoun, but what is the "der" ("der den Briefträger") exactly? What function does it have? Is it the definite article for "Briefträger" and if so, the relative pronoun must be placed between the article and the noun?