Tlemcen is a Berber Iqta in the Maghreb region of north Africa. It borders Morocco to the west, Tunis to the east and Mzab to the south. It is Sunni and follows the Maliki school. It is the primary nation of berber culture.
Costal Raiding is a naval ability added in the Mare Nostrum expansion which allows fleets belonging to nations with the Raid Coasts idea to raid the coasts of other nations of a different religion for loot (ducats) and sailors. The Golden Century DLC introduces Pirate Republics and Custom Nations with the Pirate Republic government. This idea is also available to Custom Nations. Pirate Republics, Normandy, Somalia, and countries with Norse ideas may also raid coasts of countries with the same religion.
Historically, this ability reflects the raids carried out by Barbary pirates which were active in the Mediterranean Sea during the mid-16th to early 19th centuries while in the case of the three Pirate Republics, it simulates the Golden Age of Piracy in the Caribbean Sea from the mid-16th to the early 18th century. So is a special case, as it represents a resurgence of the Japanese Wokou Pirates that raided the coasts of East Asia intermittently from the 4th century to the 17th century.
Raiding can provide a significant early-game boost to the income and sailor pools of nations that can do it and can also serve as a way to damage the economy of other nations. An example of this is So, which can employ Coastal Raiding against Ming to pile up devastation and cause Ming to potentially lose the Mandate of Heaven and collapse.
The below is one of many player suggested strategies for Tlemcen. Bear in mind, due to the dynamic nature of the game, it may unfold differently for other players.
Tlemcen starts the game with the looming threat of partition, between Morocco and Tunis. However Morocco starts out friendly and thus can be allied, but the player must maintain a diplomat as Morocco is inclined to end the alliance at any time. With the partition threat somewhat removed, the recommended first move would be fabricating a claim and declaring war on Mzab before Tunis does so. It is recommended to leave Mzab as a vassal with its Ibadi province, but to take the other one, so the player can fabricate claims on Touggourt, if Tunis has not annexed them already. Touggourt and Djerid can be fully annexed in a similar manner. Once the player has eliminated these nations, seeking an alliance with the Mamluks or the Ottomans (if they have gotten to Tunis already) is recommended. Ideally, neither Morocco nor the Ottomans ally Tunis and the player can annex them with Mamlukean help. Usually, however, this is not the case. If Morocco has allied Tunis, the player should strike when it inevitably gets in trouble with the Iberians, as an attack from both nations can quickly destroy Tlemcen. If Tunis is allied to the Ottomans, it is recommended to hire lots of mercenaries, going into debt and the player should do it on their own, as calling in the Mamluks would give the Ottomans access, destroying all hope of victory. While waiting for an opportunity, the player could try to get Exploration ideas, so that the Saharan desert can be colonized once the Southern provinces of Tunis have been taken, granting the player access to a very rich region, which will be necessary to recover from debt gathered through the war with Tunis.