HMS Monnow

The River class was a class of 151 frigates launched between 1941 and 1944 for use as anti-submarine convoy escorts in the North Atlantic. The majority served with the Royal Navy and Royal Canadian Navy (RCN), with some serving in the other Allied navies: the Royal Australian Navy (RAN), the Free French Naval Forces, the Royal Netherlands Navy and, post-war, the South African Navy.

A frigate is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat.

The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service.

A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used in a non-military sense, for example when driving through remote areas.

The Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. The campaign peaked from mid-1940 through to the end of 1943.

World War II or the Second World War, often abbreviated as WWII or WW2, was a global conflict that lasted from 1939 to 1945. The vast majority of the world's countries, including all of the great powers, fought as part of two opposing military alliances: the Allies and the Axis. Many participants threw their economic, industrial, and scientific capabilities behind this total war, blurring the distinction between civilian and military resources. Aircraft played a major role, enabling the strategic bombing of population centres and the delivery of the only two nuclear weapons ever used in war.

The River Monnow marks the England–Wales border for much of its 42 miles (68 km) length. After flowing through southwest Herefordshire, England, and eastern Monmouthshire, Wales, its confluence with the River Wye is approximately 1⁄3 mile (0.54 km) south of Monmouth.

The Royal Canadian Navy is the naval force of Canada. The RCN is one of three environmental commands within the Canadian Armed Forces. As of 2021, the RCN operates 12 frigates, four attack submarines, 12 coastal defence vessels, eight patrol class training vessels, two offshore patrol vessels, and several auxiliary vessels. The RCN consists of 8,570 Regular Force and 4,111 Primary Reserve sailors, supported by 3,800 civilians. Vice-Admiral Angus Topshee is the current commander of the Royal Canadian Navy and chief of the Naval Staff.

The Royal Danish Navy is the sea-based branch of the Danish Defence force. The RDN is mainly responsible for maritime defence and maintaining the sovereignty of Danish territorial waters. Other tasks include surveillance, search and rescue, icebreaking, oil spill recovery and prevention as well as contributions to international tasks and forces.