The Battles of the Pentapolis (otherwise known as the Pentapolis Battles) were a series of conflicts for the Pentapolis on the Adriatic, formerly part of the Exarchate of Ravenna. The Pentapolis was composed of five cities: Ancona, Fano, Pesaro, Rimini, and Senigallia. From 913 until 920, the Pentapolis was deadlocked in the Pentapolis Battles. Led by Landulf until 918, at which point Atenulf III assumed the role as Head of the League, the Pentapolis battles were an effective stalemate for several years until the betrayal of Sicily in 920, at which point the League faltered and was expelled altogether from the Pentapolis.
Following the successful invasion of Spoleto by Atenulf I, the League began expanding its military, hoping to eventually take out the Carolingian Papal States. His rule after the invasion, however, was short-lived; he died in 910, leaving Landulf the leader of the League of Napoli. Landulf, ascertained that the Carolingians would be expecting an attack on the Papal States and, therefore, the idea would be unfeasible due to a high troop presence in the former Papal States. Landulf distracted the Carolingians with several skirmishes in and around the Papal State's former borders before invading the Pentapolis itself.
First Battle of Ancona
The First Battle of Ancona, the southmost city in the Pentapolis, occurred in 913. Launched by the League of Napoli, the First Battle of Ancona was a decisive Napolitan victory. With the Emirate of Sicily providing naval support, the League of Napoli was able to not only quickly secure Ancona, but also hold it against Carolingian counterattacks in 913 and 914 along with attempts to retake the city throughout the decade, none of which were successful. For much of the Pentapolis Battles, Ancona remained a Napolitan city.
Battle of Senigallia
The Battle of Senigallia took place in 914 between the Carolingians and the Napolitans. Like the First Battle of Ancona, the Battle of Senigallia was a clear and concise victory for the League of Napoli. Despite Carolingian attempts, Sicilian ships proved to be too much of an obstacle once Senigallia was taken. In a similar fashion to Ancona, Senigallia rarely changed hands until 918 immediately following Landulf I's death.
The Scourge of Fano and Pesaro
Unlike the previous cities, Fano and Pesaro changed hands several times over the course of the Battles of the Pentapolis. In late 915, Fano was taken by the League of Napoli. Pesaro, a stone's throw away from the city of Fano, was next on the Napolitan hit-list. Pesaro held its own until March of 916, when the Napolitans overtook the city. A counterattack by the Carolingians occurred later that year, retaking the city successfully. The city once again fell under Napolitan rule in 918, though the Carolingians were again able to reclaim Pesaro and Fano that year due to Landulf's death.
The Second Battle of Ancona
Following the death of Landulf I and the betrayal of the Sicilians, Atenulf III was unable to keep the Carolingians at bay. In 920, a naval invasion took Ancona by force while Carolingian armies marched from Northern Italy to finish the job, thus ending the Battles of the Pentapolis.
The Battles of the Pentapolis proved to be a costly endeavor for both the Carolingians and the Sicilians, along with the League of Napoli. The fleets were decimated following the battles in the Adriatic Sea, though the Carolingian army was able to quickly recover from the Battles of the Pentapolis. The League of Napoli, on the other hand, suffered from fewer resources, leading to its demise. While it can be asserted that the fact that the League of Napoli saw its height during the Battles of the Pentapolis, it must also be remembered that, along with the Sicilian betrayal, the Pentapolis Battles directly led to the collapse of the Napolitan war effort.