Question: When was the coastal defense fortification located east of downtown Portland built?

Context articles: Piti Guns
Fort Popham
Fort Baldwin
Munjoy Hill
Scharzfels Castle
Yongfeng-class coastal defense ship
Odin-class coastal defense ship
List of coastal defense ships of Germany
Ranisstorum
Fort Sumner (Maine)

The Piti Guns or Piti Coastal Defense Guns is the site of three Vickers-type Model 3 140 mm coastal defense guns in the War in the Pacific National Historical Park in Piti, Guam.
 The Japanese manufactured these Model 3 coastal defense guns in 1914.
 During the Japanese Occupation of Guam from 1941-1944, they built up defensive positions on the island.
 The Chamorro population was forced to work in building up these defenses, and did so here at the Piti Guns.
Fort Popham is a Civil War-era coastal defense fortification at the mouth of the Kennebec River in Phippsburg, Maine.
 It is located in sight of the short-lived Popham Colony and, like the colony, named for George Popham, the colony's leader.
Fort Baldwin is a former coastal defense fortification near the mouth of the Kennebec River in Phippsburg, Maine, United States.
 It was named after Jeduthan Baldwin, an engineer for the Continental Army during the American Revolution.
 The fort was constructed between 1905 and 1912 and originally consisted of three batteries.
Munjoy Hill is a neighborhood and prominent geographical feature of Portland, Maine.
 It is located east of downtown, and south of East Deering, the neighborhood it is connected to by Tukey's Bridge.
 The neighborhood historically had a large Irish and Italian American population.
Scharzfels Castle (German: "Burgruine Scharzfels" ) is the medieval ruin of a fortification located east of the village of Scharzfeld in the borough of Herzberg am Harz in central Germany.
 It lies in a wood on a ridge about 150 m above the Oder valley.
 For centuries after its construction in the 10th or 11th century it remained an impregnable fortress.
 The inner ward is built on a dolomite rock outcrop about 20 m high.
 The castle was first captured after a siege in 1761 during the Seven Years' War and then blown up.
The "Yongfeng"-class coastal defense ships were a class of four Chinese coastal defense ships built by Japan and China respectively, each building a pair.
 Due to their small size, these ships are also frequently referred as gunboats.
The "Odin" class was a pair of coastal defense ships built for the German Kaiserliche Marine in the late 19th century.
 The class comprised two ships: "Odin" , named after the Norse god Odin, and "Ägir" , named after the Norse god of the same name.
 The ships were very similar to the preceding "Siegfried"-class coastal defense ship s, and are sometimes considered to be one class of ships.
In the 1880s, Germany built a series of coastal defense ships to protect its coastline on the North and Baltic Seas.
 During the 1870s and early 1880s, the Imperial German Navy had built a number of ironclad warships of various designs.
 In the mid-1880s, however, dissatisfaction with the "Sachsen"-class ironclad s and the rise of the "Jeune École" doctrine persuaded Leo von Caprivi, then the chief of the Imperial Navy to turn away from capital ship construction in favor of coastal defense ships and torpedo boats.
 As a result, the next class of large warships, the "Siegfried" class , was significantly smaller than the earlier ironclads, and armed with a main battery of only three large-caliber guns.
 These vessels were intended only for defense of German harbors.
 Six of them were built between 1888 and 1894.
 Another two ships of the "Odin" class were built to a modified design between 1892 and 1896.
Ranisstorum is the name of the Ancient Roman fortification located east of Sarmizegetusa, the former capital of the old kingdom of Dacia.
 The exact location of this fortification is now lost, but it is possible that it was the present location called Sub Cununi, near Gradistea de Munte in Romania.
Fort Sumner was a coastal defense fortification on Munjoy Hill in Portland, Maine, United States.
 It was built in 1794 as part of the First System of coastal fortifications built by the United States.
 It was reportedly originally named Fort Allen after the nearby Revolutionary War battery that probably became part of Fort Sumner, but was renamed in 1797 after Increase Sumner, the incumbent Governor of Massachusetts, of which Maine was then a part.
 The location is now Fort Sumner Park, also called Standpipe Park, at 60 North Street.