The main Vedic tribes remaining in the Indus Valley by 550 BC were the "Kamboja", "Sindhu", "Taksas" of Gandhara, the "Madras" and "Kathas" of the River Chenab, "Mallas" of the River Ravi and "Tugras" of the River Sutlej. These several tribes and principalities fought against one another to such an extent that the Indus Valley no longer had one powerful Vedic tribal kingdom to defend against outsiders and to wield the warring tribes into one organized kingdom. The area was wealthy and fertile, yet infighting led to misery and despair. King Pushkarasakti of Gandhara was engaged in power struggles against his local rivals and as such the Khyber Pass remained poorly defended. King Darius I of the Achaemenid Empire took advantage of the opportunity and planned for an invasion. The Indus Valley was fabled in Persia for its gold and fertile soil and conquering it had been a major objective of his predecessor Cyrus The Great. In 542 BC, Cyrus had led his army and conquered the Makran coast in southern Balochistan. However, he is known to have campaigned beyond Makran (in the regions of Kalat, Khuzdar and Panjgur) and lost most of his army in the "Gedrosian Desert" (speculated today as the Kharan Desert).