Naval history resists hard period boundaries

Naval history fits poorly into rigid periods with clean start and end dates. Technologies, hulls, and operating roles overlap for decades instead of replacing one another all at once. A ship of the line fighting at the Battle of Lissa illustrates the survival of an older type into the ironclad era, while other such hulls remained afloat in secondary functions after dreadnoughts entered service. Labels such as age of sail, ironclad, and dreadnought describe dominant patterns rather than instant fleet-wide transitions.