This is a rough estimate of the timeline for human and Hrasi interaction. Emphasis on the 'rough' - it's by no means canon, just something I sometimes use as basic reference. If there's a conflict with something in a story, the story is probably right. If there's something that just doesn't make any sense at all... well, bear with me...

There is a lot of jumping between the Hrasi and the Human timelines, but it's not the difference between calendars. Something has been doing some temporal mucking-around-with between our worlds - this is alluded to near the end of BL.

Hrasi time line:

667 - The northern provinces fall into disarray: Yoichi period of unrest takes hold.

703 - Lord Hesmenthe Yoichi takes control of the northern provinces, uniting them together.

712 - Voyager II crashes in Higa province. Lord Yoichi quickly confiscates it. Rrsai, a new religion, appears.

826 - Sergio Gerevsky and his USSR MiG-27 lands in Asra'nn province. Again the artifact is taken to the northern provinces for study after Sergio is killed.

828 - Rrsai becomes the dominant religion, based around the 'gifts of the gods' that were the human ships.

1034 - A B-2 stealth bomber and crew disappear from their middle-east airbase and reappear in the Soffos mountains. Both pilots die, but Rrsai's sway over the masses is strengthened.

1227 - Open rebellion among the provinces, inspired by the church, throws Hrasi culture into a 100-year war and an ensuing 300-year dark age

2042 - The first Hrasi airplane is built (average flight time 8 seconds from level takeoff).

2090 - The Discovery II crashes in the Mandal plains. Dr. Rachel Mitchell is the only survivor. Civil war breaks out at the realization of her technological level.

2091 - Dr. Mitchell finds asylum with the beleaguered Yoichi province. Their advanced technology brutally puts down the other's insurrection. (note: OBSOLETE. I decided to change it.)

2096 - The doctor's willingness to provide technology comes to an end and with Yoichi's pressuring for weaponry. Her last interrogation session provides Yoichi with her unique propulsion theories. (also obsolete.)

2100 - With the fall of the Rrsai, Discovery II, Voyager II, the MiG, and the B-2 come under total analysis.

2359 - The first Hrasi conversion drive-equipped ship, the Lifeblood, is constructed.

2361 - The Hrasi reverse-engineering process completes and their primary fleet's construction begins.

2383 - The Hrasi's fleet is constructed and it begins its methodical retracing of  the steps to Sol.

2384 - On March 6th the fleet enters the Har El Ibli system only to find it already colonized...

Human time line:

1977 - Voyager II launched.

2000 - 43rd President (Bush) elected; ISS construction begins.

2180 - Mitchell particles discovered.

2182 - Discovery II disappears into the atmosphere during landing attempt: losses include three astronauts, two cosmonauts, and theoretical physicist Dr. Rachel Mitchell.

2240 - 83rd President (Orinoko) elected.

2242 - Orinoko assassinated; ICA takeover begins.

2245 - US falls.

2246 - UN falls.

2248 - Takeover complete; Immediate expansion programs begin.

2253 - The first conversion drive-equipped ship, the Peking, constructed.

2261 - Planetary terraforming begins on Venus.

2262 - Planetary terraforming begins on Mars.

2277 - Planetary terraforming begins on Pluto.

2290 - Earth's atmosphere becomes lethal near the equator; concealed-habitat cities are common.

2320 - Sol system has been colonized to full capacity, including all moons.

2346 - White dwarf system Har El Ibli is discovered along with its desert world.

2364 - Mercury is harvested to form Earth's shipyard 'ring'. Earth's native biosphere has been fully destroyed and the surface is no longer hospitable to life.

2369 - Har El Ibli is first colonized.

2384 - Ibli Prime is attacked by the Hrasi fleet (March 6th). In two hours forty million people are dead, six orbital batteries are destroyed, and an additional five hundred have been captured inside their twenty system defense ships.

2392 - The Hrasi are met in fleet-to-fleet battle at Delta Pavonis; destruction of the human fleet is utter.

2393 - By audio message the Hrasi formally declare war upon ICA; Sol's diplomatic corps is dissolved.

2401 - The war continues to the nearly exclusive victory of the Hrasi. The battle is taken within Sol, all the way to Saturn.

2402 - The Flight Academy on Tycho turns out the first bomber division, the first in a series of ace pilots. They fight back the Hrasi, regaining Sol, Har El Ibli, and Tau Ceti.

2450 - The fighting continues.

2507 - Present Day.