Understand Italian used by Leonardo da Vinci: fable 1

Favola 1

Il cedro ambizioso

Avendo il cedro desiderio di fare uno bello e grande frutto in nella sommità di sé, lo mise a seguizione con tutte le forze del suo omore, il quale frutto, cresciuto, fu cagione di fare declinare la elevata e diritta cima.

— Leonardo da Vinci

Here is my translation of the fable:

The ambitious cedar tree
The cedar tree, wanting to bear a nice, large fruit at its top, carried out its wishes with all its might; but once the fruit had grown, it caused the tall, straight top of the cedar tree to droop.

For study purposes, here now is a literal translation of the fable, including accents in the Italian to show the stressed syllable of a word:

Il cèdro ambizióso (the ambitious cedar)
Avèndo il cèdro (having the cedar) desidèrio di fàre ùno bèllo e grànde frùtto (desire to make a nice and big fruit) in nélla sommità di sé (in the summit of itself), lo mìse a seguizióne (it carried it* out) con tùtte le fòrze del sùo omóre (with all the forces of its disposition), il quàle frùtto (which fruit), cresciùto (having grown), fu cagióne di fàre declinàre (was the cause of making descend) la elevàta e dirìtta cìma (the elevated and straight top+).

*its desire
+of the tree

In this fable, there are two words that refer to the top of a tree: la sommità and la cima. These words are not limited to talking of treetops; they could also be used to talk, for example, of the tops of hills and mountains: la sommità della montagna (mountaintop), la cima della collina (hilltop), etc.

The expression mettere a seguizione means to carry out, to put into effect. In the fable, you find mise a seguizione (it carried out), where mise is the third-person singular, passato remoto conjugation of the verb mettere. Example: Il cedro mise a seguizione il suo desiderio (the cedar carried out its desire).

The masculine noun omore is an antiquated equivalent of the modern umore, meaning temperament, disposition, mood.

The expression essere cagione di means to be the cause of, where the feminine noun cagione means cause, reason. In the fable, you find fu cagione di (it was the cause of); fu is the third-person singular, passato remoto conjugation of the verb essere. Other examples: fu cagione di dolore (it was the cause of pain), fu cagione di molti danni (it was the cause of much damage).