Bis take accusative but what about Bis zum Morgen grauen

I still don't understand this.
In Bis zum Morgen grauen, graunen could be acc or dat since morgen is masculine, but in Bis zum nächten Mal,   nächten  must be dat as Mal is neuter so I assume grauen is also dat. How is this an example of bis taking the accusative?

Hi sfpugh,

Zu can only take the dative case (there's a catchphrase that goes "Von AusBeiMit nach SeitVonZu, fährst immer mit dem Dativ du").

Bis, however, can only take the accusative, but many times it is combined with zu, and it is this last preposition that governs the following elements in the sentence.

I hope this helps!

Lucia

Ok, thanks I get it it but... how is it an example of bis taking the accusative. Surely it would be better to find a simple example or at least to explain what is going on in this example is used.