Why Did the Athenians Build a Third Long Wall?

David H. Conwell

            During the mid-fifth century B.C., the Athenians built three great fortification walls to connect the inland city of Athens with the port cities of Phaleron and Piraeus. The first two Long Walls were in place by the end of 458, and a third was built by 431. That the Long Walls safeguarded communication between Athens and its navy clearly justifies the first two of these structures. Why the Athenians decided to build the third—or Middle—Long Wall, however, remains an open question.

            Scholars have proposed a variety of explanations, all of which typically share the assertion that the Middle Wall replaced the structure which joined Athens and Phaleron. Some believe that the structure corrected strategic flaws in the original design. Proponents of this view suggest either that the Athenians regarded the long stretch of unprotected coastline between the first two walls as too vulnerable or that these structures were too widely spaced to be defended adequately with the available manpower. Others link the new structure to the declining importance of the port at Phaleron relative to the harbors at Piraeus. However plausible these suggestions seem to be, they generally overlook the ancient evidence.

            Ancient accounts explaining the function of the Middle Wall are few and far between, to be sure. Thucydides writes that at the beginning of the Peloponnesian War in 431, the original two Long Walls were guarded, whereas the Middle Wall was not (Thuc. II.13.7). This passage does not suggest why the Athenians built the latter structure, but it does indicate that their third Long Wall was not a primary line of defense. Only a late commentator explains the structure’s purpose (schol. ad Pl. Grg. 455e; Olymp. in Grg. 7.3). This testimony states that the Middle Wall served as a backup ensuring Athens' connection to the sea in case an enemy successfully stormed either one of the original two walls. On the face of it, the comment is problematic, for the third Long Wall cannot have backed up both of those structures. Such a fortification wall would have possessed towers—and therefore stairways—along either face, thus providing attacking forces with ready access to the wall-walk. Moreover, archaeological evidence now demonstrates that in fact towers lined just one face of the Middle Wall, while stairways lined the other.

            Nevertheless, the commentator's basic principle—that the structure served during an emergency—matches the evidence provided by Thucydides. The agreement of both written sources on this key point leads to two conclusions. In the first place, one may reject the assumption that the third Long Wall replaced the structure linking Athens with Phaleron. Secondly, although the third Long Wall cannot have backed up both of the original structures, it can certainly have served as a secondary line of defense behind one or the other of the original Long Walls. Indeed, excavated evidence for towers along the southern side of the structure indicates that the wall was directed towards attacks from the south. Therefore, the Athenians built their third Long Wall in case an enemy bypassed the wall joining Athens to Phaleron.