| Singular | Plural | |
|---|---|---|
| Nominativ | diadema, diadema | diademae, diademata |
| Genitiv | diadematis, diademai, diademae | diadematium, diadematum, diademarum, diademum |
| Dativ | diademae, diademai, diademate, diademati | diadematibus, diademis, diademabus |
| Akkusativ | diademam, diadema | diademas, diademata |
| Ablativ | diadema, diademate, diademad | diadematibus, diademis, diademabus |
| Vokativ | diadema, diadema | diademae, diademata |