THE SEQUOIA 
and then followed the establishment of the Mohammedan re- 
ligion, which, during the next one hundred and fifty years, 
reached the zenith of its power and threatened to overrun the 
whole world. This Saracenic invasion was checked at the battle 
of Tours (732), in which the Franks under Charles Martel 
overwhelmingly defeated the Mohammedans. The beginning of 
the next century was marked with the crowning of Charlemagne 
on Christmas day, 800. This monarch made a noble effort to 
educate his people by establishing a school at his court and in- 
viting thither the few learned men of his time. 
The climatic conditions in California during a.p. 800 and the 
year preceding must have been very favorable for the growth of 
our tree, which had already attained the size of a large elm. Its 
growth during these two years, indicated by the large rings, was 
phenomenal. 
During this century occurred also the effort of King Alfred to 
establish schools in England. The hardy Norsemen began their 
bold voyages in quest of treasure and adventure, colonized Ice- 
land in 874, discovered Greenland (981), and pushing farther west- 
ward probably sailed down along the eastern shore of America. 
The Crusades, begun in 1o96 and continuing for almost 200 
years, brought the various European peoples into intercourse, 
which resulted in exchange of ideas and helped prepare the popu- 
lar mind for the discoveries which were soon to follow. 
The first half of the thirteenth century saw the founding of 
the universities. First, the University of Paris (1200), which 
became the center of theology; a few years later were founded 
the University of Bologna, famous for law, and the University 
of Padua, which attracted the greatest students in medicine. 
In England, Oxford University was founded in 1249. 
The fifteenth century brought those marvelous discoveries 
which were of so much importance in the advancement of civil- 
ization, and which contributed to the growth of science. Print- 
ing with wooden block type was introduced by John Gutenberg 
in 1438, and his invention was followed in 1450 with the use of 
metal type, making the general dissemination of knowledge 
possible. 
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