[FOM] der Morgenstern ist die Venus

[Dean Buckner]

(cross posted to FOM and historia mathematica)

Frege writes (in 'On Concept and Object') 

Im Satze "der Morgenstern ist die Venus" haben wir zwei Eigennamen
"Morgenstern" und "Venus" für denselben Gegenstand.

which Geach translates as 

In the sentence 'The morning star is Venus' we have two proper names
'morning star' and 'Venus', for the same object.

Note that Frege says 'die Venus' rather than 'Venus'.  Is this standard
practice in German, or is Frege's German idiosyncratic?