426 THE INSCRIPTIONS AT COPAN. 
(9.11.15.0.0) and the foundations of Mound 26 being laid 42 years later 
(9.13.18.17.9). Doubtless we must also assume that during these 57 years 
other temples had been built east of the site of Mound 26, corresponding to 
the lower plaza-levels in the cross-section of the Acropolis exposed by the river. 
Mound 26, the Hieroglyphic Stairway on its western side, Temple 26 
on its summit, and Stela M at its western base, an undertaking involving a 
great outlay of labor, had been completed and were dedicated in 9.16.5.0.0, 
45 years later. Meanwhile, work on the substructure on the south side of the 
Court of the Hieroglyphic Stairway was going forward, and 5 years later, 
in 9.16.10.0.0, Stela N was erected, and less than 3 years later, in 9.16.12.5.17, 
the very important Temple 11 was dedicated and another large section of the 
Acropolis completed. 
Although we have no dates to guide us here, we may doubtless assume 
that toward the close of the Middle Period, 7.e., during the course of con- 
struction of Mound 26, the part of the Acropolis lying to its south was also 
changing shape, gradually being built higher, and reaching the next higher 
plaza-levels in the cross-section exposed by the river on the east side. 
During the 8 years between 9.16.12.5.17 and 9.17.0.0.0, the Acropolis 
received its final additions. The whole southwestern corner marking the 
Western Court was probably filled in and dedicated in 9.17.0.0.0, as indi- 
cated by the date on the Reviewing-stand at the northern end of this court. 
At the same time the whole eastern side of the Acropolis was also raised 
to its final levels, Temples 21 and 22 being dedicated some time between 
9.16.12.5.17 and 9.17.0.0.0, and Temple 214 on the latter date. 
Judging from the rapidity with which these several parts of the Acrop- 
olis seem to have been successively completed, as indicated by the dates 
actually recorded upon integral members of this architectural complex, 
the writer believes it is probably safe to assume that the Acropolis was not 
commenced much, if any earlier than 9.11.0.0.0 and possibly not before 
9.13.18.17.9, and was completed in 9.17.0.0.0, that is to say, it was probably 
something between 60 and 120 years in building. 
Returning now to the general history of Copan during the Middle 
Period, we may probably assume that the Main Structure was founded in 
g.11I.0.0.0, or at least became the most important settlement in the valley 
from that date on, soon eclipsing Group 9, which had hitherto been the 
capital of the region. 
Moreover, of the other five groups founded at the same time, not one has 
another monument of any date, and it seems probable that, at least in so far as 
these particular groups were concerned, all the architectural and sculptural 
efforts of the tribe were centered on the construction and embellishment of 
buildings at the Main Structure. This appears clearly in the second column of 
Appendix [X, where, after 9.11.0.0.0, it will be seen that the only settlement in 
the valley outside of the Main Structure at which monuments were erected 
during the Middle Period was Group 8, midway between the Main Struc- 
