Medieval crossbow prods made of wood, horn/baleen and sinew, was the bowstring kept tight and the bow permamently bent like a steel bow or was it kept slack and only tightened when drawn? Does anybody have any info about this? Oddbjørn.

Hello Oddbjørn!

I think they were all, (or most of them at least), "permanently bent like a steel bow".
One thing that confuses this is that there are crossbows at museums where the string lays slack on the bow, but this is because its to hard/risky to try and span a 400 + years old crossbow.

Micke D,
Stockholm LockbowSociety,
Sweden

If these bows were permanently kept strung, even though they were of a composite manufacture, I wonder how long it would be before the limbs would take a "set" and lose their efficiency? Perhaps the limbs were just simply replaced from time to time as they lost their cast? Does anyone have any thoughts on this?

Generally, a strung composite bow loses some of its effectiveness over a long period of being strung. A horn/wood/sinew composite hand bow loses about 20 to 30% of its strength if strung for a long period. However, it reaches a stable weight with in the first week or so and is dependable after that. As a result of this behaviour, it is likely that highly reflexed bows were strung at the beginning of an expedition and unstrung and corrected at the end. Reflex can be almost completely recovered by unstringing. In addition, leaving the bow belly-up in the sun for a few days will bring it close to its original weight.

While a composite crossbow lath is not exactly comparable to a hand bow, mainly because of the wooden bellies, it would be logical to treat it the same way. Bows associated with city militias could have been strung for extended periods and then rested during the remainder of the year. Most of these militias and associations probably had their own bowyers paid from common funds. Mercenary crossbowmen probably kept their bows strung for the duration of the campaign they were hired for unless there were occasions where they were free from potential action and the bows needed servicing.

The lesser reflex of the European crossbow laths would have made them less sensitive to being strung for a long period since it would reduce the tension in the braced bow compared to highly reflexed hand bows. It is important to consider that bows in museums are not stored in anticipation for them being shot again so their condition is not a good indicator of how their original owners would have treated them. Bracing the bows would have been done with a bastard string so the effort would be no more than was involved in drawing them. I do not suggest that a bastard string was carried by every crossbowman, but it would have been included in the equipment of any group of soldiers.

Bede, Thanks very much for your information -- very helpful!