Caesaris liber: De Bello Gallico

I’ve got a query about Caesar’s “De Bello Gallico”. I’m translating the 7th book and I found the word “conventus”(1st section). What’s this conventus?
I don’t need a translation but I need to know what this conventus was and why Caesar had to go back to Italy “ad conventus agendos”.

Perseus has a note on this passage that Italiam means Cisalpine Gaul (http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0017&query=book%3D%237). L&S has agere conventum = to hold a court (http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0059&layout=&query=entry%3D%2310988&loc=conventus).[/url]