Descartes and Pascal were initially sent to French Indochina in the late 1890s, where they participated in the campaign to suppress the Boxer Uprising in Qing China.

In the late 1880s, the Italian Regia Marina (Royal Navy) accelerated construction of ships for its fleet and reorganized the most modern ironclad battleships—the Duilio and Italia classes—into a fast squadron suitable for offensive operations.

To compound matters, the visit of a German squadron of four ironclads to Italy confirmed French concerns of a combined Italo-German fleet that would dramatically outnumber their own.

In addition to twenty-four new battleships, a total of seventy cruisers were to be built for use in home waters and overseas in the French colonial empire.

[2][3] To meet the requirements for new cruisers for overseas deployments, the French naval minister, Édouard Barbey, issued a request on 4 November 1890 for design proposals similar to the older Lapérouse and Villars classes.

Barbey laid out his requirements for the Conseil des Travaux (Council of Works), which included a maximum displacement of 2,500 t (2,461 long tons; 2,756 short tons), a speed of at least 16 knots (30 km/h; 18 mph) at natural draft, and a cruising radius of 4,500 nautical miles (8,300 km; 5,200 mi) at 10 knots (19 km/h; 12 mph) with a normal load of coal (and up to 6,000 nmi (11,000 km; 6,900 mi) with a maximum load).

De Bussy's design was in general arrangement and enlarged version of the cruiser Davout, with the same hull lines, with roughly the same length to beam ratio.

The Conseil selected de Bussy's design, but made a number of alterations to it, including increasing the scale of armor protection, as well as replacing the planned Lagrafel d'Allest water-tube boilers with Belleville models, as they would provide a superior internal arrangement.

Several alterations were done to Descartes only, including lengthening the forecastle deck to add crew berthing and shortening her funnels, which caused her to roll excessively.

Below the waterline, the hulls were covered in a layer of wood and copper sheathing to protect them from biofouling on long voyages overseas.

[6][7] The ships' propulsion system consisted of a pair of 4-cylinder vertical triple-expansion steam engines driving two screw propellers.

Their machinery was rated to produce 8,300 indicated horsepower (6,200 kW) for a top speed of 19 knots (35 km/h; 22 mph), but in service, both ships exceeded these figures.

[14][15][16] Descartes returned to France in 1902, when she joined the Atlantic Division,[17] though Pascal remained in East Asia.

Pascal's condition deteriorated after several years abroad, where the French lacked sufficient shipyard facilities, and by 1904, her engines could no longer reach her design speed.

She saw little further use thereafter, in part because the French Navy had settled on building a fleet of armored cruisers to fulfill the roles that the Descartes class had been intended to fill.

[25] By 1914, the ship was operating with the Atlantic Division; she was patrolling in Central American waters and was slated to return to France when World War I started in July.

She instead remained in the region and joined the French and British vessels searching for the German light cruiser SMS Karlsruhe that was attacking merchant shipping in the area, though they failed to locate her.

After returning home in 1917, she was decommissioned and disarmed, her guns being used as field artillery and to arm patrol vessels.