Peaceful Infiltration Model
In 1925, Albrecht Alt [N] published (in German) “The Settlement of the Israelites in Palestine,” which set forth his view of the seminomadic Israelites’ infiltration of the central highlands of Canaan. Working primarily with Egyptian sources from the Late Bronze Age, Alt concluded that the central highlands were only sparsely settled at the time. At the end of the Amarna period, around 1350 BCE, Shechem was the only significant city-state in the hill country between Jerusalem and the Jezreel Valley. A century later, when the power of the 19th Dynasty pharaohs collapsed, the hill country still seems to have been relatively free of occupation.  This is the region where biblical traditions locate the initial settlements of the Israelites.
Alt’s view of how the Israelites acquired this thinly populated region is trenchant: Since little resistance would have been encountered in the wide gaps in the city-state system, a gradual settlement resulted from seminomads following their flocks year after year from east of the Jordan River into the hills west of the river. Eventually these seminomads began to build villages and become sedentary. Thus, the settlement occurred relatively peacefully, rather than by military conquest as indicated in Joshua 1–12.
Alt’s pupil, Martin Noth [N-1] developed this “gradual settlement” approach further, spelling out a more detailed scenario. Noth contended that tribes developed over time as the various seminomadic elements settled down in different parts of the hill country. Eventually, some of these tribes formed an alliance; and the alliance was expanded in stages until there were 12 tribes. In this way, 12-tribe Israel came into existence. By closely analyzing the tribal lists in the Pentateuch, Noth attempted to trace the stages by which the tribal confederacy expanded to 12. He was guided also by what he believed to be similar alliances in the Greek world (known there as amphictyonies).
According to the Alt-Noth model, therefore, “Israel” was a tribal confederacy, with Yahweh as the God of the confederacy and the Ark of the Covenant its central (mobile) shrine. The people who composed the 12 tribes, or at least their ancestors, had entered the land from beyond the Jordan River. But Israel itself, the tribal confederacy, came into existence only after the people were in Canaan.  Manfred Weippert, Noth’s pupil, summarized the Alt-Noth view as follows:
This tribal confederacy did not exist at the time when those who later became the Israelites entered Palestine … One must suppose, rather, that it was a question of individual clans or confederacies of clans of nomads with small cattle (sheep and goats) who, during the winter rainy season and the spring, lived with their herds in the border territory between the desert and the cultivated land and who were forced, when the vegetation in that area ceased in the summer, to penetrate further into the cultivated land and to come to an understanding with the owners of the land about summer pasturage in the harvested fields and in the woods.
The clans who entered the country in this way in the course of regular change of pasture then gradually settled in the relatively thinly populated wooded areas of the uplands, areas which were not directly exposed to the reach either of the Canaanite city-states or of Egyptian sovereignty, and began to practice agriculture once they had turned these wooded areas into arable land. This peaceful process of transition on the part of nomads to a sedentary life was, according to Alt, the real process of settlement and it was, in the nature of things, a peaceful development, since the interests of any landowners there might be would not be harmed by it.” 
Military encounters, Alt and his students believed, occurred in a second stage of Israelite settlement, which Alt characterized as “territorial expansion.” However, this was late in the period of the Judges and the early monarchy, when Israel expanded into the plains and valleys that had long been occupied by groups of Canaanites. Also it was a long process during which the Israelites won some fortified cities but also lost some battles. Presumably, the memory of these wars would account for what Abraham Malamat characterizes as “  a basic element of Israelite consciousness … that Canaan was ‘inherited’ by force.” In any case, the military confrontations came at the end of the 11th century BCE, when the tribes were beginning to coalesce into a monarchy, instead of at the end of the 13th century BCE, when they first entered into Canaan. 
Alt’s view, which fits better with the Book of Judges than the Book of Joshua, sparked more than a half-century of controversy with Albright, his pupils, and other scholars, such as Yadin and Malamat, who favored the military conquest approach. Some parts of Alt’s arguments were very persuasive, however, and still are. As we shall see below, for example, the gradual settlement approach seems in keeping with the available archaeological evidence. During the first two centuries of the Iron Age (beginning in about 1200 BCE), some two or three hundred small settlements were planted in the more or less empty hill country of central Palestine.
The major weakness in the Alt-Noth position was its dependence on the sociological theories of Max Weber, who drew a sharp distinction between the lifestyles of villagers and those of nomads. Alt characterized the earliest Israelites as nomads who, like modern Bedouin, followed their flocks seasonally into the highlands after harvest and exploited any weakness they found in the control of the territory. Lacking specific evidence, Alt and his students worked from analogy based on the sedentarization of Bedouin in this century and conjectured that the same process occurred in the Israelite settlement. More recent sociological theory recognizes, however, that agriculture and seminomadism probably were not such sharply divided lifestyles during ancient times. As we shall see below, it may well be, in fact, that the early Iron Age settlers of the central hill country were primarily farmers and only secondarily herdsmen.
Concluding that the early Iron Age settlers were primarily farmers would not necessarily preclude a gradual settlement process rather than military conquest. But another interesting hypothesis that commanded serious attention for a time does in fact presuppose settlement under less than peaceful circumstances.
Biographical note : [N] - Albrecht Alt (1883 – 1956), was a leading German Protestant theologian. In 1908 he was a scholarship holder of the German Evangelist institute for Antiquity and undertook his first Palestine journey. In the same year he became a supervisor of the theological College in Greifswald. he was again appointed a professor in Basel, then Probost of the Erlöserkirche in Jerusalem. In 1921 he was appointed to the Halle University, in 1923 to the University of Leipzig, although he was given one year off to completion of his activities in Jerusalem.
[N-1] Martin Noth (1902 – 1968) was a German scholar of the Hebrew Bible who specialized in the pre-Exilic history of the Hebrews. He taught at Bonn, Göttingen, Tübingen, Hamburg, and University of Basel. He died during an expedition in the Negev, Israel.
 Albrecht Alt, “The Settlement of the Israelites in Palestine,” in Essays on Old Testament History and Religion, trans. R. A. Wilson (Garden City, NY: Doubleday, 1968), pp. 175–221; originally published in German in 1925.
Alt, “Settlement of the Israelites”, pp. 199–201.
 Martin Noth, Das System der zwölf Stämme Israels, Beiträge zur Wissenschaft vom Alten und Neuen Testament 4:1 (Stuttgart: W.)
 Kohlhammer, 1930), and A History of Israel, 2nd. edition, trans. Peter R. Ackroyd (New York: Harper and Row, 1958).
 Manfred Weippert, The Settlement of the Israelite Tribes in Palestine (London: SCM Press, 1971), pp. 5–6.
 Abraham Malamat, “How Inferior Israelite Forces Conquered Fortified Canaanite Cities,” BAR 08:02, March/April 1982
 Weippert, Settlement of the Israelite Tribes, pp. 5–6.