dative case

Several vestiges of the ancient dative survive in contemporary usage, most obviously εντάξει but also doxa to theo and en pasi peritposi, which is sometimes confusing even to SMG speakers

https://e-didaskalia.blogspot.com/2017/12/blog-post_295.html

Students of Ancient Greek and other languages with a dative form may understand the indirect object function of the genitive better with reference to the transferred function of the dative. This history may also help students understand the use of the accusative for the same function in northern Greek.

The dative function as indirect object has been replaced with the genitive in SMG and by the accusative in northern dialects.