"Ich sehn' mich nach der Isar Strand." — Why not "dem"?

Question

Is this really correct?

"Ich sehn' mich nach der Isar Strand."

Should it not be dem?

Answer 1

Short answer

Ich sehn' mich nach der Isar Strand.

Here, der Isar is a so-called preposed genitive that prececdes the dative noun Strand.

Long answer

Construction with dative

The phrase sich nach etwas sehnen demands the dative. Examples with all grammatical cases are:

• Ich sehne mich nach der Insel. (feminine singular)
• Ich sehne mich nach dem Haus. (neuter singular)
• Ich sehne mich nach dem Strand. (masculine singular)
• Ich sehne mich nach den Inseln/Häusern/Stränden. (plural)

Now, we want to refer to a particular beach: the Isar beach. In German one can use the compound noun Isarstrand, the gender of which is determined by the last composite, Strand:

Ich sehne mich nach dem Isarstrand. (masculine singular)

Alternative construction with genitive

The content of the previous sentence can be expressed in another way using a genitive:

Ich sehne mich nach dem Strand der Isar.

In this construction, the genitive der Isar is postposed, i. e., it succeeds dem Strand. In general, genitives may also occur preposed, especially when they involve a proper noun or when the construction is a fixed phrase. In this case, the article is omitted, which in the following examples I indicated by striking them through:

• Evas der Freund
• meines Vaters das Haus
• meiner Mutter das Haus
• meines Herzens die Qual
• Des Kaisers die neuen neue Kleider
• Der Widerspenstigen die Zähmung

and also

• der Isar dem Strand

The use of preposed genitives can still be found today, although they are perceived by many people as archaic:

Des Weltmeisters Gedächtnis lässt bereits nach (Überschrift in der Neuen Zürcher Zeitung vom 23. Juli 2018, S. 35).
^{(Source: Wikipedia)}

Now, let's turn to the original sentence

Ich sehn' mich nach der Isar Strand.

From what we have learned so far, der Isar Strand is a valid preposed-genitive construction, in which the preposed genitive der Isar precedes the dative noun Strand.

Answer 2

This is just a supplement to Björn Friedrich's neat answer.

If one omits "der Isar" as the genitive attribute belonging to "Strand", one gets "Ich seh'n mich nach Strand". One can of course criticize that a "dem" is missing ("Ich seh'n mich nach dem Strand"), but the meaning is nevertheless absolutely clear. In the case of abstracta the omission of the article is completely usual: "Ich seh'n mich nach Ruhe / Liebe / Aufmerksamkeit ... ". For the concretum "Strand" this is possibly unusual, but not at all incomprehensible.

Moreover one has to look at the context: As user9551 comments, the phrase is a line of a poem by empress Elisabeth of Austria. Here is a longer quotation:

...
Aber war ich die Frühlingswonne
hier in dem fernen, fremden Land?
Ich seh'n mich nach der Heimat Sonne,
Ich sehn' mich nach der Isar Strand.
...

It is obvious that empress Elisabeth chose a poetic formulation which forms a rhyme with "Land". And let's face it: It sounds much better than a grammatically faultless formulation, likewise "der Heimat Sonne". Besides, in the latter case "Ich seh'n mich nach Sonne" is absolutely correct even in the absence of an article.

An alternative would have been "Ich sehn' mich nach dem Isarstrand", but this sounds not as nice, especially following after the line "Ich seh'n mich nach der Heimat Sonne".

Let me finally mention that constructions of the form "noun with (attributive) prenominal genitive" are not that unusual as one may believe if one reads "der Isar Strand". However, frequently they have an antiquated touch, and constructions of the form "noun with (attributive) postnominal genitive" seem to be prevalent. I think the following is a general rule:

A noun requires an article if it occurs with a postnominal genitive. Example: Er wartet auf das Urteil des Richters.
An article must not be used if a noun occurs with a prenominal genitive. Example: Er wartet auf des Richters Urteil.

In other words, a prenominal genitive "absorbs" the article. In fact, there is no adequate position for an article - it simply does not fit before and not after the prenominal genitive. In some dialects one uses ugly phrases like Er wartet auf dem Richter sein Urteil or Der Dativ ist dem Genitiv sein Tod. Here the possessive pronoun "sein" is a sort of substitute for the omitted article - but that cannot be a serious solution.

Here are some more examples for prenominal genitives.

• Des Kaisers neue Kleider.
• Viele Jäger sind des Hasen Tod.
• Jeder ist seines Glückes Schmied.
• Des Mannes liebstes Spielzeug ist sein Auto.
• Das also war des Pudels Kern.
• Des Trainers Ansehen ist gewachsen.
• Er sah Annas Vater. [This is the usual construction when used with names, altough also Er sah den Vater Annas or Er sah den Vater von Anna are in use.]

See also here for a more rigid linguistic treatment.