The title of "oldest castle" is debated among historians, but Windsor Castle in England is one of the strongest contenders. Built in the 11th century by William the Conqueror¹, it has been continuously inhabited for over 900 years, making it the longest-occupied palace in Europe. Another ancient fortress² is the Citadel³ of Aleppo in Syria, dating back to the 3rd millennium⁴ BCE, though much of its current structure is medieval.

In France, Château⁵ de Doué-la-Fontaine (10th century) is considered the oldest stone castle, while Hohensalzburg Fortress in Austria (1077) remains⁶ one of Europe's best-preserved medieval castles. These structures reflect early military architecture and feudal⁷ power.

关于“最古老的城堡”存在争议，但英国的温莎城堡是最有力的竞争者之一。它由威廉征服者于11世纪建造，至今已连续使用900多年，成为欧洲居住时间最长的宫殿。另一座古老堡垒是叙利亚的阿勒颇城堡，其历史可追溯至公元前3000年，不过现存结构多为中世纪所建。

法国的杜埃拉泉城堡（10世纪）被认为是最古老的石制城堡，而奥地利的萨尔茨堡要塞（1077年）仍是欧洲保存最完好的中世纪城堡之一。这些建筑展现了早期军事防御和封建权力的演变。