Peribsen

The king was considered to be the incarnation of the heavenly god Horus (who took the form of a falcon), and his name was inscribed within the framework of a palace called a serekh, which was topped by a falcon. At the end of the Second Dynasty, forces opposed to the strengthening of the monarchy supported King Peribsen, causing chaos in the country for a time, but King Khasekhemui succeeded in reunifying the country, and the authority of the king was finally established.
[Old Kingdom]
With the Third Dynasty, the centralized state with the king at the apex was completed in both name and reality, and ancient Egyptian civilization entered its first period of prosperity.

*Some of the terminology explanations that mention "Peribsen" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…王は天の神ホルス(隼（はやぶさ）の姿をとる)の化身とされ，王名はセレクserekhと呼ばれる隼を頂く王宮の枠内に記された。第2王朝末，王権強化に反対する勢力がペルイブセンPeribsen王を擁立，国内は一時乱れるが，カセケムイKhasekhemui王が再統一に成功，王の権威は最終的に確立する。
［古王国時代］
　第3王朝とともに王を頂点とする中央集権国家は名実ともに完成，古代エジプト文明は最初の繁栄期を迎える。…

※「Peribsen」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報