CABlakeC
06-10-2019

It's questionable if this court rank title really exists or not. According to the Japanese wiki, you need a combined total of 1.4 mil fame to obtain it, which until recently, was not possible. However I have yet to see or hear a player to get this title. I also spoke to [CA]Huseyin_Gazi who is maxed out in all levels and fame, and he got no notification after a lot of investing, doing discoveries, etc. Even one player on the Japanese Wiki commented he couldn't get it either despite being maxed out and doing what it takes to gain court rank titles (but then, where did they get the info for the Archduke title? Hmm...).

Beomi
03-04-2020

After Lost Memories chapter 3 update, you can obtain this title.

Required levels: 90/90/90
Required fame: 1.5m (The player who got this title said he couldn't obtain it when his fame was 1.4m

Source: www.inven.co.kr/board/dho/603/4640 and
gvo.gamedb.info/wiki/?Peerage
(Thank you guilder!)