1900s in the context of Decade

1908 (MCMVIII) was a leap year starting on Wednesday of the Gregorian calendar and a leap year starting on Tuesday of the Julian calendar, the 1908th year of the Common Era (CE) and Anno Domini (AD) designations, the 908th year of the 2nd millennium, the 8th year of the 20th century, and the 9th year of the 1900s decade. As of the start of 1908, the Gregorian calendar was 13 days ahead of the Julian calendar, which remained in localized use until 1923.

This is the longest year in either the Julian or Gregorian calendars, having a duration of 31622401.38 seconds of Terrestrial Time (or ephemeris time), measured according to the definition of mean solar time.

1907 (MCMVII) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1907th year of the Common Era (CE) and Anno Domini (AD) designations, the 907th year of the 2nd millennium, the 7th year of the 20th century, and the 8th year of the 1900s decade. As of the start of 1907, the Gregorian calendar was 13 days ahead of the Julian calendar, which remained in localized use until 1923.

Pre-dreadnought battleships were sea-going battleships built from the mid- to late- 1880s to the early 1900s. Their designs were conceived before the appearance of HMS Dreadnought in 1906 and their classification as "pre-dreadnought" is retrospectively applied. In their day, they were simply known as "battleships" or else more rank-specific terms such as "first-class battleship" and so forth. The pre-dreadnought battleships were the pre-eminent warships of their time and replaced the ironclad battleships of the 1870s and 1880s.

In contrast to the multifarious development of ironclads in preceding decades, the 1890s saw navies worldwide start to build battleships to a common design as dozens of ships essentially followed the design of the Royal Navy's Majestic class. Built from steel, protected by compound, nickel steel or case-hardened steel armor, pre-dreadnought battleships were driven by coal-fired boilers powering compound reciprocating steam engines which turned underwater screws. These ships distinctively carried a main battery of very heavy guns upon the weather deck, in large rotating mounts either fully or partially armored over, and supported by one or more secondary batteries of lighter weapons on broadside.

1901 (MCMI) was a common year starting on Tuesday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1901st year of the Common Era (CE) and Anno Domini (AD) designations, the 901st year of the 2nd millennium, the 1st year of the 20th century, and the 2nd year of the 1900s decade. As of the start of 1901, the Gregorian calendar was 13 days ahead of the Julian calendar, which remained in localized use until 1923.

December 13 of this year is the beginning of signed 32-bit Unix time, and is scheduled to end in January 19, 2038.

1900 (MCM) was an exceptional century common year starting on Monday of the Gregorian calendar and a leap year starting on Saturday of the Julian calendar, the 1900th year of the Common Era (CE) and Anno Domini (AD) designations, the 900th year of the 2nd millennium, the 100th and last year of the 19th century, and the 1st year of the 1900s decade. As of the start of 1900, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.

As of March 1 (O.S. February 17), when the Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day farther behind, bringing the difference to 13 days until February 28 (O.S. February 15), 2100.