Most Fritillaria seed need some sort of after ripening before germination, so they are usually planted in the early to mid fall and come up in the following spring. (Although myself, I still find significant germination a year after that.) The exception might be with some of the Norh American species.
Some fritillaria seed germinate at 70F and some at 40F. F. persica germinates at 40F ((4C). The best germination of 40F germinating species I have ever had was one spring when normal days had 50F highs: we had a snowfall that completely covered the ground and my frit pots about 1.5 inches. Temps hovered at 30-40F. The snow stayed for 2-3 days before melting. In the following days I had better germination of 40F germinators then ever before.
You might also want to search Ian Young's bulb log here:
http://www.srgc.org.uk/logs/in...
Ian is a world guru on fritillaria and bulb plant growth in general. I was very fortunate to have him stay at my house for a few days. One of the coolest, knowledgeable people I know, and you could spend a year reading his bulb logs....