Dom Carlos I, from 1910 NRP Almirante Reis, was a Portuguese Navy cruiser of the early 20th century, the only ship of its type.

It represented a typical protected cruiser design of the British Armstrong shipyard in Elswick of the turn-of-the-century period.

During World War I, it was withdrawn from active service due to wear on its boilers, and was struck from the fleet list in 1925.

The ship was built as part of a program to strengthen the Portuguese Navy in the 1890s, announced by royal decree on March 20, 1890.

[3] It was ordered from the Armstrong Whitworth shipyard in Elswick, England, and represented a typical example of the so-called "Elswick cruisers" that were built for export for many fleets, with the direct model for the design for Portugal being the Yoshino built earlier for Japan.

The bow superstructure was small, and the ship's silhouette was completed by two massive masts and two thin tall chimneys amidships, in the middle of the hull's length.

[7] The hull was steel, covered in the underwater part with a layer of wood and copper sheet.

[7] The hull was double, and additional side protection in the boiler and engine room area was provided by coal compartments (cofferdams [pl]) typical of cruisers of the period.

[9][10] The remaining artillery was positioned on the sides, and the last pair of 120 mm guns could fire towards the stern.

[d] The 47 mm caliber guns were placed in positions in the sides at the bow and stern (two pairs, firing forward and aft), amidships and on the lower battle marts.

[7] The maximum coal reserve was unusually large for a ship of this size and allowed for a long range of about 10,000 nautical miles (19,000 km; 12,000 mi) at 10 knots (19 km/h; 12 mph), suitable for service in the Portuguese Empire.

[5] In January 1901, Dom Carlos I represented Portugal at the celebrations in Portsmouth for the funeral of Queen Victoria.

[16] In June 1902, it took part in a naval revue on the Spithead roadstead outside Portsmouth to celebrate the coronation of Edward VII, with Portuguese heir to the throne Prince Luís Filipe.

In September 1907, Dom Carlos I became part of the Training Squadron, grouping the most valuable ships.

[16] In 1908, the king whose name the ship bore was assassinated and his successor Manuel II ascended to the throne.

[16] However, this strained the ship's boilers, which needed repairs, and meant that it was no longer used actively in the remainder of the war when Portugal joined the Triple Entente side in 1916.

[18][4] According to one version, the ship's hull was then seized by the Dutch navy before being bombed and sunk by the Germans in 1940, but there is no reliable confirmation of this story.