ADMINISTRATIVE GEOGRAPHYedge of the desert from the Euphrates near Hit, through the region of
oases called Taff to the sea near the later site of Basra. This line was
fortified with watchtowers and barracks for garrisons to prevent bed-
ouin attacks on the cultivated land of Iraq and was regarded as the
effective boundary between Iraq and the Najd.^170 The remains of these
fortifications may still be seen at sites such as Dab" southwest of
Ukhaydir, Qasr Ruda at Wadi Burdan, and building A at Qusayr
South, sixty kilo meters southwest of Nasiriya, while a Sasanian watch-
tower called al-Qa'im survives on the Euphrates below Salhiyya.l7l
The line of oases called the 'Uyun of Taff is especially associated with
the northwestern end of the khandaq. They included 'Ayn Sayd,
Qutqutana, Ruhayma and 'Ayn Jamal, where the land was assigned
for the use of the Arabs and Persians who defended the border.172
After the battle of Dhu Qar, Arabs took over part of the 'Uyun of
Taff while the Persians kept the rest. The foundation of Qadisiyya
just inside the khandaq by Khusraw Parviz was part of the reestab-
lishment of this frontier in the early seventh century.173 By the time
of the Muslim conquest, the estates in the 'Uyun of T aff were held
by members of the highest Persian aristocracy,174 the fortress of Qasr
Muqatil, west of Qutqutana, was held for the Persians by a garrison
under an-Nu'man ibn Qabi~a a!-Ta'i,175 and the oasis of 'Udhayb
beyond the khandaq was garrisoned as a Persian border post.^176
There was little reason for the Muslims to maintain elaborate de-
fenses against a desert they controlled. Thus after the conquest this
line of Persian fortifications was either abandoned or put to other uses.
Some of the fortresses may have survived as way-stations along the
desert road between Basra and Kufa or became centers for farming in
170 R. Frye, "The Sasanian System of Walls for Defense," in Studies in Memory of
Gaston Wiet (Jerusalem, 1977), pp. 8-11; Ibn Rustah, A'laq, pp. 107-8; Gibson, Kish,
p. 24; Musil, Middle Euphrates, pp. 111,347-48,351; H. Nyberg, "Die sassanidische
West-grenze und ihre Verteidigung," in Septentrionalia et Orientalia (Stockholm, 1961),
pp. 316-26.
171 B. Finster and J. Schmidt, Sasanidische und fruhislamische Ruinen im Iraq (Berlin,
1977), pp. 26, 44-47, 53-54; Musil, Middle Euphrates, pp. 14-15.
172 BaladhurI, Futul;, pp. 297-98; Yaqiit, Buldan, 1II, 539-40, 549.
173 Al-'An:,"Min~aqat al-I:I1ra," p. 21; Tabari, Ta'rtkh, I, 2233, 2543; Qazwini, Athar
al-hilad, p. 159; Yaqiit, Buldan, IV, 42-43.
174 Tabari, Ta'rfkh, I, 2247.
175 AI-'Al:i:, "Min~aqat al-Kiifa," pp. 246-47; Tabari, Ta'rfkh, I, 2350. For the iden-
tification of Qasr Muqatil with Ukhaydir or Tulul al-Ukhaydir, see Finster and Schmidt,
Ruinen, pp. 149-50.
176 AI-'Ali, "Min~aqat al-I:lira," p. 20; Musil, Middle Euphrates, p. 111; Tabari,
Ta'rtkh, I, 2231.